Nurses and teachers love them, too. Credit: Travel + LeisureFor some reason, I’ve always associated slip-on sneakers with people older than me. What’s the big deal with tying laces, unless bending or crouching is a big inconvenience? And although I’m quite flexible (thanks, yoga!), I recently discovered the advantages of slip-ons, thanks to a pair of Allswifit walking shoes I got last year.As an everyday shoe, I love the ease of stepping into th…