I've had my plant for about 15 year now in the same pot. My plant is looking a bit limp on one side. This is the side that's closest to the wall. I have been thinking of repotting the plant but don't know if it's a good idea. Can you help with a few suggestions. Thank you. Sue
I would rotate the plant to help even out the amount of sunlight. This should be done even weekly to help the plant.
The soil is probably very tired and may be lacking in nutrition or even salts can build up in the soil from conditioned water and fertilizer.
I would not repot your plant until it is done blooming. Then you can repot, using either the same container or only choosing a new one that is slightly larger.
You can add a trellis to the new container to help support your vine.
To large of a container can lead to root rot.