These 2 have been in the same pots for about 3 years and I have a few others as well. i do lift them each spring and remove about a 1/3 of the root ball and add new soil. The key to keeping them alive is not over watering in the cooler times of the year and for me none at all from about mid october to mid april when they are in the garage dormant. If one happens to wrinkle of winter I will give it some water to plump it back up. My go to technique for that last few years has been to put the pot in a trash bag and seal it up to the trunk. Seems to help hold just enough moisture for the winter.
I have also been planting some of the bigger ones directly in the ground each spring and then digging up in fall to store. This works very well however Im noticing that they seem to spend more energy rooting back in and not so many blooms. The plant grows so much better this way and i dont have worry as much about watering but not having as many flowers is a bummer. I may stop doing this and just sink the whole pot in the ground to simulate them being planted.
the white-flowered plumeria with glossy foliage are actually tough as nails, will survive several days on standing water. Also drought-tolerant like other cultivars, which makes it an ideal ornamental tree to grow in areas of periodic ‘feast-or- famine’