It is one of the reasons why, if I do strength training, I use dumbbells. It is a lot easier tell something is too heavy when you pick it up instead of setting a machine and guessing.
I think that's why we need to start light. Really widens that line out a lot, and when you do overdo it and hurt yourself it won't be by much. Working to failure is good; it means you've done all you can and aren't slacking off by not working hard enough, and the best definition of "failure" I've seen is "form breakdown", e.g. you can't control the weights, or you need to start swearing to do another rep. Work until you can't, then stop. As you get used to exactly where that line is, you can go heavier.
Personally I'm using 3 sets of 15 as a guideline. If I can't get anywhere near that then it's too heavy. If I can nearly do it then I need to keep working on it. If I can routinely exceed that then it's time to go heavier.
IANAPT, started on this a few months ago, just sharing what I've picked up so far. Of course there are lots of different views on how many sets of how many reps you should do, but bear in mind what works for A won't necessarily work for B, especially if A is a chiselled Greek god and B is a somewhat lardy me who can literally roll up to the gym.
doing lots of reps on something well within your range also trains your endurance, which is generally pretty important and something that people who just want big biceps can easily forget.
I've had great success with being lazy and quitting early. I changed majors. I didn't stick with guitar because I didn't enjoy the practice itself, but I've been doing martial arts for over twenty years. Had a bunch of short relationships until I found the one that stuck. Every job has been better than the last because I knew a bunch of things I hated about the ones before to avoid and kept growing my skill set. Quitting something is great.
I made that decision with a Game Boy emulator project. I got to a certain point of implementing op codes, and realized that I was bound for a long list of tedious but simple code. The stuff I did do worked as far as it went. The world does not need another Game Boy emulator; there are tons of good ones out there already. I had learned enough to get an idea of how emulators function, and that was good enough for me.
Me working with a wordpress theme that just does not work and wordpress itself making my life harder because partially I know barely anything and second this shit is not fit for me!!!!!