Originally Posted by Mikefule

If you have track ends (sometimes referred to as horizontal dropouts) then you can move the wheel forwards or backwards a bit. Too much movement and you will have problems with your brakes.

I find that I can change my sprocket by 1 or 2 teeth without it being a problem. A 14 tooth sprocket is 12.5% bigger gear than a 16t, or a 17% lower gear than a 12t. Either pairing should be different enough for most purposes. A flip flop hub with sprockets carefully chosen and 2 teeth apart in size gives you quite a range.

There is a physical limit to how much torque you can apply, but you can learn to spin faster. Therefore, if in doubt, choose a gear that will get you up the steepest hill on your route at a reasonable speed, and hope you can spin that fast on the steepest descent.

Yes, you can swap the chain ring as well. It is not a big job, but it is expensive to have a selection of chainrings as well as a selection of sprockets. Add 1t to the sprocket and take 1t off the chainring and you can keep the same chain length — this works within reason. Remember that a 1t difference on the chainring makes only a tiny % change to your gearing.

As for breaking your chain, it is not a major thing. Some people do that regularly just to clean their chain. The tool to do it is cheap and easily available. You an buy the pins or links cheaply, although personally I consider it unnecessary to use a new pin each time.