The only time it takes is the time to be attentive to your child and effort to keep them out of a wet or dirty nappy. The longer I do it, the less I understand how I rationalised keeping DS in wet nappies (no matter how absorbent) and letting him poo in his pants - the more I consider how awful it must feel to sit in your own waste until you don't care anymore (what happens with full-time nappying in babies after a while, and I'm convinced this has something to do with fussy and unsettled babies and babies that wake fussing after a 20-40 min sleep - just coincidence that this is the average length of deep sleep and humans feel the need to eliminate just after a deep sleep cycle when coming into lighter sleep??).
Anyhow, I consider it takes more time out of my day to tend to nappy washing or even nappy disposal (if you're doing the legal thing of taking the poo off the sposie instead of sending it to landfill) than to lovingly hold my baby over a receptacle and then rinse her bum. Because it's an extension of your relationship with the baby, once you start doing it, it doesn't feel like another task, it's just part of your interactions and to consider it taking time would be like considering giving your baby a cuddle taking time out of your day, IYKWIM. It just becomes the thing you do as part of parenting your baby. If all I do during the day is feed, play with and help DD do her wee and poo I feel I've done my work and everything else becomes a nice-to-have-got-done.
My sister said the same thing - she'd like to try it (and her DS was about 9 months old when my DD was starting EC) but she didn't think she'd have the time. I didn't give her a spiel, just said that once I started I never looked back and it doesn't feel like it's a time stealer - the hardest part is just starting when you haven't done it before, because in our culture it's a leap of faith...and I put it off!
I guess most times now I treat it like BFing - it's what we do and there are no options to put a nappy on at night to avoid overnight pottying. Eventually, she'll get through the night without either a BF or pottying. I can do either now without fully waking and we both just drop right off when I lay her down again. And I find night time pottying the easiest to keep on top of - no pressure to be doing something else like continuing a conversation, cooking dinner, putting out washing, gettign somewhere in the car (though I find lately that for shorter trips she waits till we stop to do a wee and on longer trips will fall asleep and wake giving us warning so that we can pull over safely and use an icecream container inside the car, give her a feed again, swish water in the container and fertilise the nature strip
Anyway, obviously people have great relationships with kids when they do nappying, and when my DS was out of nappies I decided that the only thing I'd change about my parenting with the next one was that I'd do EC, because I was really happy with the way I was instinctual in every other way the first time round
So, just give it a go and see what happens in yourself, your baby and with your time.