Just got a miniature schnauzer puppy last Saturday with my gf and we couldn't be happier
He's 10 weeks old now but the breeder gave me a pretty strict schedule to follow:
7am: out to potty for 15 mins
in to eat for 15 mins
out to potty for 15 mins
in to play for ~45 mins
back into crate to nap
12pm: repeat
5pm: repeat
9pm: repeat, except we do not feed him at this hour.
Needless to say, it would have been impossible for us to find time for him if I wasn't in between jobs right now. I'm sure the schedule will vary from breeder to breeder, but a dog will take more time and more devotion than you think.
Does your apartment have a balcony? My breeder recommended that if you have a balcony that you close off any gaps where the puppy could jump out and cover the balcony with astroturf. You can potty train him outside on the balcony, he can play out there, and you can just hose off any pee or poop.