The more the better, but also keep in mind that very often, tactics are NOT the main limiter of your rating.
I suspect it's actually more common at the class level to make so many positional errors and positional blunders that losing tactics are just super easy to fall into. But looking at the tactic and thinking you could have studied more tactics to avoid it isn't the right solution - the solution is to understand the positional elements so you won't even get into that sort of risky situation in the first place.
Strong players play games where it seems like their opponents have all the blundering/losing chances, and they almost have to intentionally drop pieces to lose. Often times, they can even blunder pieces, but their position is so strong that they win anyway.
If you're doing tons of tactics but your rating isn't going anywhere, this is likely a big part of why.
That's what I like about Chesstempo tactics wise, not a social site so your ratings are pretty much private.