I have a great deal of respect for those with some time in the program who have the wisdom to do a 90 in 90.
Many people feel 90 in 90 is just for newcomers but anyone with any amount of time can reinforce their program.
I did an 89 in 90 once.

On day 90 I left one meeting when it was half-over and quickly sped to the last half of a different meeting, claiming two meetings for that day... my sponsor wasn't buying it, lol.