Re: Time out for a 19 month old?
19months is definitely not too young to understand time outs. My friend started at 15months and he understood. Eventually.
that being said............ I don't like timeout for the exact situation you described. Reason being: they do not want you to be changing their clothes, etc. That is what they are battling against. So, if you stop and put them in timeout, then they win. They didn't want their diaper changed, they didn't want pajamas, etc and now they're not getting it. That's positive reinforcement for them to do the same thing next time.
And 19months is definitely too young to do the whole 'timeout after momma is done' thing because at this age, the education needs to be quick for them to understand 'why' it's happening.
We mostly just ignore it during clothes or diaper changes. Or we try redirection with tickling, etc.
the only time I really think timeout is effective is when it's for something like hitting or throwing themselves into a tantrum - because then they need a little time to regain their control.
of course, my child is now the type who throws herself on the floor and mockingly says 'timeout?' (she's 26 months). So, for me, it's really only effective when she needs time to regain her control.
SAHM to Magnolia May (09/10), Luke Russett (04/13) and expecting 11/16. Wife and best friend to my airman.