I do it every other day, because I work out on the off days. Between work and the munchkin, time is at a premium so I have enough time to train one thing per day. I have enough true-weight dummy rounds to fill one magazine, so I do them separately. I never practice draws with a "light" gun, because it throws the balance off. I also never practice mag changes with an empty mag for the same reason. For complete clarification, I drop an empty magazine from the gun during dry fire mag changes. A loaded mag will evacuate the magwell faster than an empty one and also hide any mild hiccups in the process.

To make sure my mag changes are slick, I have run a sander with 600 grit over the mags and give the top third a coat of automotive wax. Super slick.