Not too long. I begged, borrowed and pleaded my way into airplanes and picked up quite a few (paid) trips when I was still a wet ticket CFI. That and flight instruction, flying part 91 trips in king airs, 421s, 310s and anything I could get into and it added up pretty quick. Before I got my commercial and CFI, my friends at the flight school would safety pilot for each other all the time. That helped a ton.
I was quite a zombie for a while working 7 days a week in some cases. I've since learned that I enjoy my home life a little too much to do that ever again. :laff:
Just do what you can and make sure if you're a commercial pilot, you're being paid.
-mini