This is a hard question. My husband has been in practice 29 years. He's a solo general dentist & the early years were spent building the practice, buying the equipment, etc. The next few were buying our house, having a family, taking vacations. Then...we lost a bunch when the stock market took a dive. Now...we have 1 child in college & 1 in medical school & he's replacing X-ray equip w/ digital, upgrading computers to paperless charting, etc...its always something... We have to wait until our kids are out of school, but we realize at some point you just decide you're done. We have a bit of flexibility because I'm a pharmacist and can work as much or little as I want. But...I would recommend to put something aside every year no matter what - don't wait for later when the loan payments are lower - they never will be! Have fun!