What's wrecking all my op-amps?

[Electric-Gecko]

I have been attempting to make effects pedals for my electric bass for about a year and a half now. I have only once soldered one onto a PCB, which was a tube-screamer which didn't work. Other than that, I have only bread-boarded them, which seem to have worked the minority of the time. I use schematics from the internet, although I often make slight modifications.

I sometimes notice my op-amps becoming non-functional. Sometimes, I wouldn't know if the problem was the op-amp or the way that I built my circuit. But recently, I tested a circuit with 3 different dual op-amps. I confirmed that my long-suspectedly broken TL072 was indeed broken, and that it worked with 2 other op-amps. But then I think one of those broke later that day. I also built tried to breadboard another pedal with a new TL074 (which used all 4 op-amps), but it didn't work; just fuzzy noise. So I suspect that it somehow broke during construction or something.
I figure that many people just look at schematics, and put them onto a PCB exactly as it appears. But I tend to reuse them on a breadboard a few times, to try different schematics, and test how they work.

So end of story, what could cause op-amps to break? What should I do to prevent this?
I have found in my searches some things about input voltage, that it must stay between the supply voltages. Here's a way to use diodes to prevent the positive input from going significantly outside that range;

But some schematics use single power supplies, so the ground pin of the audio jacks are connected to the op-amp negative power input. Wouldn't this cause the input voltage to go lower than the negative power? Don't audio signals oscillate between positive and negative voltages?

I also wonder if an op-amp could be wrecked if there's no feedback path (from the output to negative/inverting input). Would the op-amp destroy itself by attempting infinite gain? What if I have unused sections of a multi-op-amp chip? Would the unused op-amps break when powered on?

[NickS]

I have found in my searches some things about input voltage, that it must stay between the supply voltages. ...
But some schematics use single power supplies, so the ground pin of the audio jacks are connected to the op-amp negative power input. Wouldn't this cause the input voltage to go lower than the negative power? Don't audio signals oscillate between positive and negative voltages?

Yes, so in this case you would use a blocking capacitor and bias the input halfway between the voltage rails.

I also wonder if an op-amp could be wrecked if there's no feedback path (from the output to negative/inverting input). Would the op-amp destroy itself by attempting infinite gain? What if I have unused sections of a multi-op-amp chip? Would the unused op-amps break when powered on?

Though it should not destroy itself (the TL07x are supposed to be short-circuit proof), open-circuit might result in oscillation so it would be good practice to ground the unused + inputs (if using balanced supply, else to your Vref) and connect the output to the - input.
Other thoughts:
- Be conservative with the voltage rails - limit them to +/- 12v.
- Although the TL07x series have some static protection built in, ensure that you are taking static precautions.
- To avoid heat damage from soldering use IC sockets.