How long can babies amuse themselves?

[Again]

My 10 week old can be put down on his mat for about 15 minutes max. I can vary things by holding him for 15, putting him on changing mat, activity mat, but I struggle to keep him amused. Is this normal? I've been told to keep him up for a few hours before bedtime, but there's no way I can do this!

that's bloody good for a 10 wk old
my ds2 is 5 mths and needs a change of scene every 10 mins, we go from pram, to floor, to highchair to jumparoo, to sling
He is tired about 1.5 hrs after waking and we keep him up from 5-7 and he goes down at 7.
We tend to give him a good strip wash or (more rarely) a bath and naked play this gets rid of half an hour and he loves it.

Poor little mite! His mum is clueless!

not at all, I've had 2 previously