I recently bought a canon AE-1. After finishing my first roll of film I went unload it and forgot to press the rewind button on the bottom before winding the rewind crank. I know… I should’ve reread an article before doing so, I really was not thinking. I ruined the film, not shockingly. But now I’m worried that by forcing it that I’ve ruined the gears in the camera. If anyone could help either ease my worries or confirm my beliefs, it would be greatly appreciated.
The first easy diagnosis you can do is to put in a new roll of cheap film. Don't try to use this roll for shots you intend to keep – this is for diagnostic purposes only. See if the camera "acts" normally with the new roll: take pictures, advance the film as normally after each shot. If it seems like it takes more cranks on the advance lever until the next frame is ready to go, that might indicate the advance gears were stripped or have some sort of problem. If the film seems to advance normally, then the advance gears are probably ok.
Shoot the entire roll. At the end of the roll, rewind the film (by first pressing the rewind button before cranking). If the film rewinds entirely, then you're probably ok.
This is a simple diagnosis you can try before you determine if you need to send it in for service. If anything acts weird or differently that expected in the above steps, then you have to consider you might have damaged the camera, and you'll have to take it to a repair shop or send it in for repair in order to get a cost estimate. Good luck!
Just use it and find out.
If it is not broken everything will be fine.
If it is broken nothing will change.
Using film always will involve some wasted rolls (and many wasted frames). If a wasted roll stops you, you will not shoot much film.
The more you use a film camera, the fewer mistakes you are likely to have. It takes practice and experience.
Equipment still breaks when you drop it on the sidewalk with a thunk and three foot dead cat bounce.