For ngondro I accumulated 1,000 per day of the relevant mantras.
I retired early and have time to devote to this, and agree that, whilst it is tempting to rattle through them, recitation is only valuable with the proper motivation, visualisations etc. as taught by your root guru.
In my case, accumulation was not restricted to retreats, but I was told it should always be in a formal setting at home. Again, I am fortunate in that I have a shrine area I can leave in place and simply enter and practise.
If at home and there is a possibility of disturbing others, I would recite silently, 'mentally', which I have been taught is acceptable.
Is it 'enough'?
Well, 100,000 is a 'target' for some purposes, and some people have commitments to recite a certain number daily, but I have never heard of 'enough?
I know some monastics who have chanted millions of mantras, but how many mantras it takes to move each person's mind to the same degree is surely an imponderable, as we all start at a different point and practice with differing effect. Imprints of past lives etc. - impossible to have any precision IMHO of 'enough'.
I think this very much depends upon the purpose of recitation. 'Mind protection', 'accumulation', as a condensed sadhana etc., maybe even praise or propitiation.
In the end, the purpose is to work on the mind, and to do so within the context of compassion, non-attachment and an understanding of emptiness.
Do enlightened beings chant mantras?
If not, I guess at the point of enlightenment we have chanted 'enough'.
What an interesting question. Thanks.
