Well, ok seeing as though you asked...
I'm embarrassed to admit that I am on MN for probably 4-6 hours a day most week days. Which now I write it down sounds like an awful lot! Some days I won't be on at all though, so that'd bring my average down I suppose.
I use MN a lot because I am a SAHM with a toddler and a baby, in a new area with only a very few acquaintance type friends. I don't have too much in the way of parental support with regards to advice on my parenting (long story there) and they and other family live too far away to be of any practical help, though I hasten to add they are supportive and loving.
MN is usually my first port of call for parenting help, in the early days for breastfeeding it was invaluable {many thanks to TikTok, forever in her debt, in fact feel teary when I think how grateful to her I am}, it has also been great for sleeping and behaviour issues - the sort of thing where you would normally be able to say to your mum 'did we do that when we were toddlers, is it normal?' I ask on MN.
It also fills a social void in my life at the moment, though I am careful to namechange frequently as I don't want to be recognised or traceable online. Moving to a new area has been hard and I miss the daily interaction I used to have with close friends. Here, if I have spent all morning saying 'if you do that again, you will go on the naughty step' I can then come on here for ten minutes and have a discussion about anything from controlled crying to the merits of the first past the post system in voting. Its an escape and gives me something to ponder whilst I am changing nappies.
I am slowly making new friends, but good close friendships are not often made overnight, so in the meantime MN is my new best friend.
So I come on MN whilst the DC have their afternoon nap and most evenings. It is my hobby I suppose is the best way of putting it and one that just about keeps me sane.