Meaning

Sir,

1.I have done it once a day for five years now.

2.I have done it once a day for five years.

What are the differences in meaning between (1) and (2).

Thanks.

It's a fine distinction. But I would say that 'now' is attached when we want to give less emphasis to a repeated action:

'What time do you get up in the morning?'
'4 am.'
'4 am! But that's terrible! Doesn't it make you very tired?'
'Oh, not really. I'm used to it. I've done it every day for five years now.'

Such sentences are most likely to occur as additional information about another fact.

So sentence #1 is less emphatic about the information it contains. Sentence #2, on the other hand, is the 'neutral' form of the sentence. You could use it in most contexts.

MrP