The last time I ventured potentially helpful advice on bike locking, I got a critically worded post in reply, saying I was a 'slave to material possessions'. Hey, okay, whatever & too Zen for me - I just want my bike to still be there.

Some suggest not over-thinking locks and insuring the bike against theft away from home. This may or may not be viable for a given individual - I looked into this for my situation and between a lowered deductible that would cover most of the value of a bicycle and a subsequent a rate increase on the entire contents of my house if I made a claim, it didn't make economic 'cents' for me. YMMV

Running random errands is the worst bike security scenario because you're often unsure what the situation will be (folks around, what there is to lock to) until you're there.

You have to balance theft deterrence (and that's all we can hope for: deterrence) with cost, weight, convenience and flexibility. So many of the variables are dependent on an individual's bike & environment that it can be hard to make specific recommendations over the internet. This doesn't stop folks from doing so; in fact, because we've each bet our bicycles that our decision is the right one, discussions can get 'testy'.

It's hard to beat the security and flexibility of a top of the line chain and top quality padlock. This will be your most expensive and heaviest option. It's hard to beat the low cost and light weight of a flex cable + combination lock. This will be the option that provides the least theft deterrence.

Two locks are better than one. Word from the street is that two less secure locks provide more theft deterrence than one more secure lock. Should you spend your lock budget on the one, best lock you can afford or two lesser, but still good locks? Sorry, too many variables to give a universal answer.

At some point, the lock(s) you use becomes less important than your locking method and what you lock to. There are a great many websites that offer advice; read several.

You don't have to outrun the bear. You only have to outrun your buddy.

Similar appearing locks can provide much different deterrence. A excellent example is Abus' 40 and 401 series U-locks. They look identical, but the 401 has better steel, better heat treatment and a better lock mechanism. Tigr's marketing video compares their $200 model with "a U-lock", which looks like one you might buy at a big box store for $15~20. Several posters in the last year had spent their money on Bordo 6000s but seemed to be under the impression that they bought Bordo 6500 level security.

A note about Bike Radar's ratings: they include cost, weight & convenience as well as security. They mark down some of the highest deterrent locks for being heavy and expensive.

With the common availability of battery powered reciprocating saws (aka 'Sawzall'), I gotta give snaps to the thieves still going old school with hacksaws.