I think I have not done any back squats for more than a year. After the hiatus I have finally decided to incorporate them once again into my training albeit with much lighter weights than before; which is saying something because I never was good at back squats and the best I could muster was 55kg for 5 reps.
I'm up to 40kg for 4 reps now. Feeling steady and sturdy. Knees aren't hurting. That's a good sign.
One tip that I've started to follow is to do a few sets of leg curls first to get those hammies warmed up and pumped before I hit the squats. It has worked like a charm so far.