Fifty is excessive but you’re better-served doing 12-20 reps more than fewer, heavier reps if you’re pushing hypertrophy and already well-trained.

That matches what I've been told by various personal trainers. 6-8 reps if focusing on strength, ~12 for all round, and 16-18 for size/endurance. Do three sets, weight should be enough that the last couple of reps on the first set are a bit of a struggle. Subsequent sets just push through as far as you can.