If they're rootbound, by all means, go for it! If they aren't then you're welcome to change the soil and place in different, but same-sized pot. It just depends on what effort you have the time and desire for. Changing soil can help evict the possible pests. I like to water my plants before I repot/change soil and wet the new soil after the move. It kinda helps keep the roots in place and they're less brittle and sensitive. You don't have to do the pre-watering though.

Did your plant already flower? Now it the time they start to flower. If you plumiera has not flowers wait until after it flowers before re-potting the plant. Once you pull the plant out of the old pot give it 4..5 day in the shade before re-potting to give the roots a chance to heal. when you remove plants from pots there is usually some root damage (fine hairs). with tropical plants you need to let the roots heal to prevent future root problems. Plumeria plants are very hardy so leaving then out of soil for an extended time is not a problem. Adeniumrose Company rare and unusual cactus, succulent plants, exotic plants and supplies.

There are actually 2 considerations for plants in direct afternoon sun through windows. One is photo load and the other is passive heat gain. The dark leaves are good solar collectors, and each leaf has what is called a boundary layer of air surrounding it that insulates the leaf. IOW, light turns to heat on the leaf's surface and the boundary layer of air insulates it from escaping into surrounding air. So, if you site your plants in front of a south or west window where it gets direct afternoon sun, it would be a good idea to have a fan on a timer to move enough air that the boundary layer of air is disrupted and heat can escape the leaf surface. The actual photo load should be no problem unless the plant is unable to adapt to what you suspect might be too much light. The plant is genetically capable of living in the (potentially) brighter light, but the leaves currently on the plant might not have the ability to make the adjustment. IOW - every leaf can't adapt to every light level. Those that are required to adapt to conditions that are outside the range they're able to adapt to will be shed and other leaves perfectly adapted to the light level where the plant is currently sited will take their place. Over-watering is probably your largest concern at this point. DO use a wooden dowel stuck deep in the pot as a 'tell', and don't water unless the 'tell' tells you the plant is dry or nearly so very deep in the pot - like all the way to the bottom. I'd be thinking about a fresh start for the plants next summer. A full repot with root pruning and a change to a soil you won't have to fight for control of your plants' vitality would be a very good move on your part. The plants will love it and you'll get much more from the growing experience when you literally see the fruits of your efforts being made manifest in your plants. Don't forget to flush the soil every month or two. It is important to help keep the level of mineral salts from fertilizers & tapwater from getting out of hand. Questions? Input? Al

Pull the tree out of its pot and look at the roots. If the roots are circling around the inside of the pot, then it is pot bound and needs repotting. Put it in a pot one size larger,