Does it make any sense to wear an automatic..

Why is a watch on your backpack? They go on your wrists. To put it on a backpack? Well, nothing about that makes much sense to me.

9mm or 45?

Knife? Maybe, but what about a small fixed blade, like gerber guardian (assuming this thread ended up in the wrong sub )

Not if you care about it. For about $40 you can get a winding stand that will keep it running. Worst thing you can do to any mechanical watch is to let it sit.

This may have been the case a while back, when the issues was lubricant gumming up or displacing, but with modern designs and lube, they can sit unwound for extended periods without trouble. In fact, there is a good case to be made against winders, as they accelerate mechanical wear.

Just have it sized and wear it on your wrist- they're fun!

,,,,,,post it to me and I'll wear it every day,,,,, I'll keep it wound and accurate and if you want to know the time just send me a text and ask

I am not entirely sure I understand the question... You want to hang an automatic watch on a backpack? Seems a bit odd - watches are obviously designed to be worn on the wrist, and if you just want a clock available then using your phone would probably be simpler and just as easily accessed than hanging something on your bag. Would I be right in assuming that you have a reason against just wearing it on your wrist like typically intended?

Either way, an auto hung from a bag that isn't used daily is going to be a bad idea on two counts. The first being that most autos typically have around a 40 hour power reserve from fully wound, so if you aren't using/carrying it pretty much daily then you are going to find it stopped fairly often. That probably comes second place to the fact I am not sure wearing it on a bag will wind it enough to keep it going in the first place - automatic watches are designed to wind during normal wrist wear, and I am not sure hung on a bag is going to give the same amount of movement. So to use the watch in this fashion with any reliability you would need to be purposely winding it regularly to keep it going which kinda defeats the idea of an automatic (wear it and it winds itself so you don't have to worry about it).

If you want a watch available then a quartz model is going to be the more reliable movement - it will be working reliably even if stationary for long periods, and as a bonus will actually run more accurately than an automatic. Opt for something like a Citizen eco-drive and you won't need to worry about batteries either as long as the watch gets a fairly steady diet of light (even just office lighting).

There also some modern quartz stopwatches that would be suitable for attaching to a pack. Some even have alarm features. Here's one of mine with a fob I made.

You can buy watches designed to be hung from things like backpacks, but I've only seen quartz ones. I wouldn't use a mechanical that way.

you could just... ya know... wear it on yer wrist

I'm with the others... no sense in strapping an auto on a backpack. Doesn't really make any practical sense.

The one Sarky posted above looks pretty neat and I just searched Amazon for "carabiner watch" and got a lot of good lookin results.

Here's the exact one I had (my dad now carries it on his keys). Dakota make a lot of this type of 'backpacking watch', and the quality is reasonable for the price in my experience. About $25 for this one, which is the most I'd spend on a watch hanging off my backpack really.

,,and then there are nurses watches,,,,,,,

And Guarddog watches... no pic but link
http://www.guarddogwatches.com

Strange posts from all over the EDC spectrum, watches, packs etc.