Wow! 20 years is amazing! You must really be good "desert roses parent".
I've had my original 5 dessert roses (now 4 only because I gave one to my neighbor) for 9 years by next month, May. But judging by the size of their caudex when I got them they may have been over 3 years old already. So I am guessing that they will be 12 years old this May. They had been neglected and had been pruned twice only. I will try not to repot them this year since i almost killed two last year from root rot.
