Anticipating principle is certaionly an option...I used to do it routinely when we were young and healthier...you know, bulletproof. Now, I build liquid cash reserves first.
They can always be turned to debt service, if you have any to do. In the meantime, they are in hand, in case a situation prevents profit for a while, and you have to bridge a gap. You can make every house poayment for nineteen years and nine months, and still lose the place if you miss the last three on a 20-year loan...it won't matter if you anticipated the majority of the principle along the way.
I would also suggest the thought that a single person supporting himself might need a disability policy, but with a transplant history, that might be impossible to obtain.
