Roughly 2000 miles on my 2017 Specialized Diverge w/Shimano BR-785 Hydraulic Disc brakes. 700 or so miles in CO then 1300 miles down here in FL. My brakes seem to work capably but the brake levers seem a little spongy. I can lock the brakes up, but also almost compress them all the way. Im wondering if I need to bleed them/replace the brake fluid? I have replaced the pads once. I think I am good there. Just not sure how often I should consider bleeding my brakes? thanks.

You might try a quick-bleed like this. This video is on a mountain bike, but the procedure is the same with road brakes..

^^^^ +1 to the quick bleed, but before you do that, just do the lever flicks as seen at the ~3 minute mark.

The internal reservoir isn't completely air-free, which is why Shimano doesn't want you flipping your bike upside-down. My guess is that sometime in the transport between CO and FL, air worked in to the lines from the reservoirs and those little bubbles just haven't worked their way back up to the reservoirs. You can also put the bike in a stand, orientate it such that the hoses are vertical and tap-tap-tap on the hoses, bottom to top, jiggling those bubbles upwards and out of the line.

In general, 2,000 miles is a very, very short interval and you shouldn't need a real bleed for quite a while.

^ Yerp.

If you don't feel confident doing it then take it to a shop.

Two or three seasons on the same fluid? Flush and fill is called for.

If the OP isn't nervous about doing a little hydraulic brake work, a simple "burp" will probably do the trick. If he's unsure, or just doesn't want to bother with it, his local shop should be able to handle it.

It's really no big deal to do the "burp".

ive gone nearly 20 years without a brake bleed on my regularly maintained crv. Are you saying that bike hydraulics are more dainty? Er, I mean susceptible to the elements. I know it is not a fair comparison but a car endures a far harsher environment than a two wheeler.

I ride rim rim brakes so don’t have any knowledge about bike hydraulics.

Naive question: Is there any reason to futz around with a Shimano system if the feel is still nice and solid?

No

The video posted above looks to be a great place to start. I am fully comfortable 'burping' my brakes. It actually looks like a fun, and interesting project. I have a feeling that will help at the very least. From there I will ride it and see if I feel any improvement. If not I will look to the full flush and bleed of my brake system with fresh fluid.
My bike started its life in with me in MN, then to CO, and now down here with me in FL so I am wondering if all the elevation changes have effected my brakes hydraulic properties? Likely not but they are def spongier than when new and I can almost bottom out the levers if I pull hard on my brakes. Thanks for the feedback!

this video is a little better than the one I originally posted.

Fluid is used because it doesn't (in a practical sense) compress - elevation change wouldn't mean a thing. As I mentioned previously, transportation usually means changes in orientation and jiggling, which can often lead to air getting on to the business side of the cylinder. Laying my bike on its side usually doesn't induce a problem if I'm driving an hour or two, but I usually need to flick the handles after longer drives, like our annual family road trip to VA.

No. I haven't bled my front Ultegra brake in 5 years. I ride steep hills, and if it were to fail, I would likely spend the rest of my life in a casket. However, there appears to be no need. Replace pads and rotors as needed, and keep the pistons clean and make sure they work and retract properly.

Yeah, I've replaced pads and fixed piston retraction issues caused by dust, but have no desire to open the vascular system without a good reason.

I opened my systems after 2+ years and the fluid hadn't even been discolored yet. A flush after 2k miles or every "two or three seasons" is proactive in the extreme.

I have 2 mountain bikes with hydraulic brakes. One is 11 years old an the other is 2 years old. I have never bled the brakes on either one.

I have ridden hydraulic disc brakes for five years and have two or more years on four bikes equipped with them. Over 100,000 miles. I bled the brakes meticulously (obsessively) when I installed them. I have never, ever had to re-bleed or replace the fluid on any Shimano hydraulic disc brake. They work exactly the same years later as they do on the day I install them.

If the initial installation is done meticulously (obsessively), there's no reason to have to maintain anything other than pads and discs as they wear out. If it was installed well, keep the hydraulic system sealed and it will be your friend for a very long time.

Shortened that for you.

...and there you go. It's because it's Shimano.

Still.... Brake bleeding hydraulic is not a rare phenomenon regardless of how well you set it up. Well designed systems that are set up correctly will usually be fine for a long time if someone is regularly riding them and generally treats their stuff well. Just like with flat tires, blown out bearings, etc you can get riders who just quite simply treat their gear like crap and don't realize it.

Coming from a mechanical background, specifically machine maintenance and repair, I am anal about proper maintenance. Flush and fill brakes on our cars every 2 years. Keeps condensation down to a minimum and proper clean lubrication to the working parts of the system. Blame my dad, he was an engineer and was very particular as to maintenance. Everything he owned worked perfectly and lasted forever. It rubbed off on me.

I still recommend flush and fill.

Yes, bicycles are designed to be simple to service for anyone with minimal DIY skills.

Cars and MCs on the other hand use paint-peeling DOT fluids, have ABS reservoirs and valves/pistons, multiple brake calipers, midpoint bleed nipples (because of routing), etc. They're significantly harder to work on and getting all their out on a fresh fill can be challenging. In addition, because of the fluids and materials, they tend to collect debris in the piston areas that should be removed (via the bleed valve). 20 years is WAY too long to not service car brakes.

It's dead easy. Even I can do it, and I dropped out of med school.

Shimano uses mineral oil which isn't hygroscopic, unlike brake fluid. Preaching waaay too frequent service isn't proper maintenance, it's just a waste.

Well, I dropped out of grad school, so we’re both handicapped.

I will bring it up the next time I am in for maintenance at Honda. Didn't mean to start a car thread.