If your cleats shift, you're going to notice. You can reposition them (especially when the cleats are new), and it's usually obvious where they should be if you look at the sole -- there's an imprint. If they're not well positioned, it can hurt, and you need to get it fixed. Fortunately, that's likely to happen during your training rides so you can fix it before you leave on your trip. (You are doing or gonna do some training, right?)

I'm something of an outlier; I couldn't find a comfortable position for SPD cleats. I switched to Speedplay Frog pedals, and have been riding them happily for about 18 years -- including a cross-country ride and several shorter rides. My reasoning goes something like this: If I pedal too slowly on climbs, my knees tell me about it. So I try to keep my cadence up. I had some experiences with landing on the top tube when I was younger, and don't want to repeat that. Clipless keeps my feet attached to the pedals so I don't slip off. Clips and straps would work, too, but for riding in town or city traffic (which happens with a certain regularity while touring), clipless works better for me than a cinched-down strap.

Ride what you want, have a great trip, have fun!

re another pair of shoes--personally I have always really liked getting out of the shoes Ive been biking in all day, and into some other ones, so thats my preference. I came to this conclusion after doing some of my early trips with only one pair of shoes, both pre clip in pedals and post. But thats my preference, and with all this rigamarol we are backing and forwarding on about, you do what you like--or try one thing, change it, or change back, it doesnt matter--just have a fun time on a bike trip.

re cleat positioning
Back in I think 92 when I got spd pedals, I got a "fit session" thing done, and in it, among all the frame dimension stuff, they had special pedals that showed your natural foot position for each foot while pedaling. It showed that my right knee had a natural position that had the heel turned in slightly towards the back of the bike, so my cleats were set up that way with a slight angle. Each time I have had new shoes or cleats, I have copied this slight cleat angle as it still just "feels right" for my right knee. I once borrowed some shoes from someone and had to do the change and felt it right away , which reminded me to angle the cleat.
So, in my case, cleat angle was a factor, but that might be a rare thing, I dont know.

so if you do use cleated shoes, ride a lot before a bike trip, and really "listen" and be aware of how your knees feel. Other factors like seat height can make knees feel odd, but the more you ride, the more you hopefully are more atune to listening to your body so to speak, so dont ignore pain or discomfort, but within reason, a generally properly setup bike should be fine as is--but do be aware that fine tuning bike fit stuff, including seat height, bar position, etc can make a real difference, and sometimes only a little change can make all the diff--but you have to ride regularly to become better at knowing and feeling what is what-it doesnt come from reading internet stuff and reading bickering anonymous interneters.

As in racing, when you're bike touring, do what you normally do on training rides or long rides. The first day of a long bike trip is not the time to introduce something new. - new shoes - new bike parts - new food. Go with what you know.

I like clipless pedals, they keep your foot securely on the pedal while allowing you to easily get them off if needed. I wouldn't go with road style clipless pedals and would want something with a cage around it to give my foot support but I think they are excellent. I have been using the PD-A530s but will be switching to the XT level PD-T8000 because they do have better grip on the platform side. Since I use SPDs on several other bikes it makes sense to be able to use them on my touring bike as well.

Personal preference. I use dual clipless/platform pedals and MTB clipless sandals. For the last year or so that's been Shimano PD-T8000 pedals with the included "multi-release" SH56 cleats and Nashbar MTB sandals. Use that for just about all riding in all conditions and the perfect combination for me. Easy to walk in and feels equally at home on clipped or platform side when riding. I use the clipped side by default mainly for consistency.

General observation. In my opinion dual purpose pedals are great if you have clipless shoes and want the occasional use of a platform. Not for long days using flats and only the platform side. I find myself clip side up more often than not and fumbling to get to the platform side to much to make it worth it on a long ride. Probably just me and I don't use the platform side enough to make it thoughtless and seamless. If I am dedicating myself to wearing regular flat shoes for something, I'll take the few minutes to swap to platform pedals.

Occasionally check your cleat bolts for tightness. I started using a thread locker (blue loctite) on my cleat bolts after losing one a couple years ago. And when touring I have a spare cleat bolt in my bag of spares.

+1 Couldn't agree with this more as they take up no space. Last year on not one but on two tours I was on, someone in the group (and not the same person) lost a screw that attached their cleat to their shoe which created a bunch of problems, they couldn't get their shoe off the pedal because the whole cleat would rotate and therefore could not become unclipped. Not fun for them until we could get a fix.

Well, I think there is that potential if the cleat is set wrong but the flip side is that, if the cleat is set right, there is less chance than with platforms.

Yep, important on both counts. Loss of a screw/bolt has happened to me once, leaving the shoe in the pedal. Didn't happen on tour, though, and I haven't needed the spare screw/bolt... so far.

Since I went clipless a couple of years ago (after decades of toe clips), I just about do exclusively clipless.

SPD. No spare shoes.

Pedals and shoes vary.

I tend to spend a lot of time on the bike, and little time off bike. So far not a lot of long multi-day trips (this decade), but hopefully that will change shortly.

I use SPD cleats pretty much all the time. I'm more comfortable with them that without them. If you like them while commuting or on leisure rides, then yes, use them for touring. But it's not a good idea to start using something new just because you're on tour. Even if you learn to use them, you may learn you don't like them. They're not for everyone. Heck, I don't even recommend them to people. I use them because I like them, not because I think they're superior for anyone else.

there are a couple magnetic pedals with a steel piece on your shoe sole (In SPD pocket) so no cleat engagement issues ..



I reworked a pair of loose fitting, slot cleat shoes, which had a lace cover flap ..

made them stiffer and the cleat slot full width and recessed, and used
a comfortable insole , and (Campy) toe clip pedals ..

All day comfort , on my bike tours that I got to take over weeks at a time..





...

And if you pedal fast enough you can create enough current to recharge your electronic devices : )

Might need a coil of copper wire to move those magnets around .. in order to do that, Mr Edison..

Bob, I'm smelling an investment idea here for us. What do you say ?

I saw a study that says it should work (just don't ask me for a citation please : )

Yes, but...

Some touring cyclists I know cover imperial centuries pretty well daily when on tour... or doing Audax rides which move 24-hour totals out to much longer distance than that. Sort of not hard to see the choice most of those riders take.

here is a reason I like being clipped in that I dont think others have brought up--I find being able to change up my pedal stroke--muscles wise--is a plus for changing up how your leg muscles work, and so gives a slightly diff muscle group use at times which feels nice.
I notice that I instinctively change up how I pedal during the day, and I think it helps with overall comfort during a long day.

Regarding cleat bolts, a lot of people think they can just install them and be done with it. But the cleat is pressed against a plastic shoe sole that over time will deform which reduces the pressure of the cleat against the shoe sole. Thus, in most cases the bolts will loosen up soon after newly installed cleats or adjusting cleat locations on a shoe. It is a good idea for the first year or so to make sure they are still tight about once a month. And I try to remember to check all my shoes once a year at the start of biking season to make sure they are all still tight, even if the cleats have been installed for a few years.

My road bike has fender mounts, but no fender or rack on the front fork. On one side I have a spare rack bolt and on the other side I have a spare cleat bolt. The cleat bolt that is countersunk, I have two washers between the bolt head and dropout so the bolt head presses against a washer instead of the dropout when I tighten the bolt.

That's a very good tip. I appreciate all the help you have given me and others here!

This makes total sense and logical and I do periodically check but I've actually experienced the exact opposite. The cleat seems to get stuck to the shoe and the screw threads form a nice tight corrosive dirt bond.

all kidding aside, its something I figure is good to mention to someone who hasnt used clipless before.
As I've made clear, it's cool that folks use what they feel like, it's just good to get some realistic "pro" reasons backed up by experience that does help in more than just the "is it more efficient" argument.

Wowser! Your first but is known to me... getting odd angles to break the hold become evident and indicate the need for tightening (after any readjustment required).

But your second point is one worth exploring for me... I have an issue on my Thorn touring bike with rear mudguard attachment. Gawd, I have probably accumulated more pedal cleat nuts/screws over time than just about any other bike part.

I actually solved a knee problem by moving to clipless from platforms: I'm not sure exactly why, but I had all kinds of knee issues when I was riding platforms. Securing my foot on the pedal resolved that and I haven't had an issue since I made the move.

To the topic at hand, I use mountain spds exclusively when I tour. I may may carry another lightweight pair of shoes depending on the nature of the trip, but I often just go with my cycling shoes. Which are very comfortable on and off the bike.

ps, I had no idea that silly graphic would be so big, it looks like I was yelling....thought it was a small thing to put in for a joke.