Rule of life: everybody's experience is different. Don't expect yours to match.
But, here's my son's example...
1) Started OTS, June '09 (Alabama), finished in Sept (3 months)
2) Moved to UPT base (Texas), waited for six months to start (attended Introduction to Flight Training in Colorado for a month). Got tired of separation and married GF in Feb '10. Started UPT in April '10, finished in following April '11 on Friday. Move #1
3) Left for survival school three days later (Monday), enroute to C-130H school (Little Rock, Arkansas). Dad and mom flew to Del Rio to help wife pack and move to Little Rock. (18 months) [Move # 2)
4) Moved into apt in Little Rock while in C-130 training, finished in Jan '12. Packed up for move to Yokota AB, Japan in Feb '12. (8 months) [Move #3].
5) Lived on base Yokota for two years, first child born mid-tour. PCS out after two years (1 year early).. (24 months) [Move #4]
6) Move to Peterson AFB, Colorado Springs. After 1 year, AF closed C-130 squadron at Peterson. Reassigned to Little Rock AFB again for upgrade to new C-130J. (13 Months) [Move #5]
7) Completed C-130J training at Little Rock. (9 months). Assigned to additional specialized C-i30 training at Kirtland AFB (Albuquerque, NM) enroute to next base in Europe. Second child born at Little Rock. Training was Temporary Duty ("TDY"), so household goods packed and sent to England. Son to New Mexico, wife and 2 kids to her parents in Virginia. (7 months) (Move # 6)
6) Complete training in NM, picked up wife and kids, flew to England where presently assigned.
NOTES:
a. Not a move every 3 or 4 years, but six moves in about six years. A bit more than average. but not too unusual for the early career years with lots of training stints at different locations. Four moves in the first six years would probably be more typical in many cases. It tends to slow down a little after that
b. Try to fit med school into that. Not easy, not impossible, but will take more separation, I suspect.
Good luck on your trip through the gauntlet. It can get stressful but its also a unique adventure and you'll see/do things most people won't ever have a chance to experience.