Young kitten's nails grow quite fast. I would clip as need, but check every few days. My 4-8 week olds got nail done twice a week sometimes. The front grows faster then the back.
As they get older, I check and clip about every 2 weeks or when I notice them being too long (which they rarely get as I keep on top of that).
I do notice they seem to want to use the scratching post more often if the nails are longer, so that might be a clue.