A bit late to the party but I find spring a bit late to split. Often they have grown a little bit..so they are a bit bigger and if they have had a little room they do put on some decent growth.
When they are in their own pots it saves so much time when you are in the busy/spring frenzy.
I've spent the last few days, cleaning out the greenhouse ready to put in all my plants/seedlings that I've moved on into bigger pots. Currently, pitting up more in the kitchen