Yes, ESCs are semi-disposable. I smoked 3 before I flew my first flight.
I buy esc's in groups of 5 (same for motors - I fly quads) then I have a spare for failure. Been using that pattern for 5+ years.
ESC's stop failing when:
- You learn how to build like a bawce (10-15 clean builds or more)
- You have the right ESC and stop shopping based on price and recommendation, and instead on specs, quality, and manufacturer.
- Your drive train is not red-line'd all the time. Get bigger than you think you need for amp handling, ESCs are self-destructive* on many levels, so you want them to run cool and without stress.
- LEARN TO TUNE - crap tunes will smoke ESC's in a few seconds
- Build and test in a controlled environment.**
* ESC's generate EM fields that pull in dirt and crap and that will fuse to the unit and decrease efficiency, among many other things that slowly kill the ESC.
** Never finish an install and go fly. Start with power up, then extended power up, then hover, then extended hover, then LoS minor workout. If the motor/esc are good then slowly ramp up to more aggressive flight. This allows you to catch a fail early, especially something easy like a tune error or mechanical resonance (very common).
Once I switch to good ESCs I stopped worrying. I am talking about KISS ESC's. I have not been able to find anything close to the performance (well FETTEC...lol). The 5" AIO's are cheap AF but easy to smoke - so I run AIO that are rated for high amps and have very few problems.
Most of the success I have in my builds is 90% skill of my build, tightness of my wiring, and tuning well.
If you are going through ESC's too quickly and there is not user error, then you need to rethink the drivetrain.