"With all do respect, don't you think it'll become meaningless, say, after the 50th time?"

I say this with very deep sincerity. It is respecting you and your own process of being divine that you would never find it 'meaningless', especially when you employ mantras with Self-respect, reverence and a quiet calm enthusiasm.

You will need proceed to prove it out for/to your personality 'self' or now conscious mind.