2 grams while on AAS is best.
While off AAS I think 1 gram per pound is plenty to maintain muscle. Your body can't use a ton of protein without being enhanced on AAS, HGH, or GH PEPTIDES.
I recommend while off AAS to take a growth hormone releaser like MK-677 to not only maintain gains, but to potentially keep making gains.
MK-677 release a dozen low wave HGH pulses per 24 hour period from only one 25mg oral dose per day. MK-677 is one amazing supplement!