Huge ponytail plant.

I have been growing my ponytail plant for around 25 years and its nearly at the roof and has shot out at different angles along the trunk.
It has not been repotted or had new soil for quite a few years.
The pot is very big. Would it kill the plant if I trimmed some roots and put new soil in so I don't have to get a pot even bigger?
I feed it during summer and it has looked so great until now. Maybe I overfed it by accident as some new growth looks brown. Or maybe I accidentally over watered it. Or maybe there is not enough dirt in it and it is root bound.
Any suggestions? Thanks.

I do not think you would have any problems at all doing this. The swollen base of the plant is a storage organ so that will help with survival. We do this at work all the time to Cycads and ponytail palms and they always live. You can be quite severe, make sure your mix is free draining.

I've got one about 15 years old.
When it was young, the dog got hold of it and smashed the pot and chewed it pretty badly. I thought it was done for, but about 18 months later I found it under the hedge and it had re-sprouted. It still has a wonky bulb where the bite marks were, but has 3 trunks and looks pretty cool

Mine is about 20 years old too, been in the ground about 4 years now, cat was using it as a scratching post, it didn’t like that, her claws got right in so we had to put sheath around it, but it survived and is growing again. They are pretty hardy,

Thanks maclad- I will trim the roots and put good quality soil back in.

Kately- when we built the house I put it in the barn and a gate toppled and broke some of the trunks and it then sprouted in all directions. They seem pretty tough.

Tourer100, I wish I could put mine in the ground but our frosts in Rangiora are too harsh. So a pot it is. Great the cat didn't harm it long term.

Appreciate your comments, thanks.