I've got DC17, DC16 & DC4. Without a doubt absolutely everything is harder with DC4.
I think this is more due to their personality than age though. The older 2 were dream babies & toddlers - slept through from 12 weeks, relatively few tantrums, both quite chilled & generally dud as they were told.
DC4 on the other hand does not. Still not sleeping consistently through the night, including last night 😴, will argue over anything, tantrums if can't have own way, not at all chilled & very high maintenance.l
DC17 & DC16 so far are still pretty chilled with no major dramas. We still have normal family issues such as putting clothes away, tidying up after yourself etc but so far that's all.
Both are fairly sensible and though go out, drink, stay out regularly til about 1am, I always know where they are, can contact them and have had no major vomiting episodes yet. DC17 now drives & has own car but is thankfully a good kid.
Last night DC4 was poorly and woke up at midnight and was crying for DC17, who was out. I phoned DC17, who answered, heard that DC4 was poorly and upset & came home to see DC4.
I think I've been lucky so far with DC17 & 16 and am fully expecting this to change when DC4 is a teenager!!