Good points Bob!
The tenant has gotten a lot better at managing expenses over the past year or so and rent has been a lot more regular. The tenant has expressed multiple times the desire to change things (paint) but never actually did so I am taking this with a grain of salt and told her we would discuss again when she is ready to move forward.
Whenever that tenant moves out, I would probably have to replace the current carpet due to age and mini blinds are also old (but functional), which is why I am considering the idea.
In any case, I would be reviewing quotes, finances and contractor and figure out a way to make sure the work will be finished before I OK the change. The old carpet will be thrown away for sure and I don't think it will be worth keeping the blinds.
If the only risk left is that the tenant leaves with the carpet and the blinds, I am OK with that.
But if the fact that the tenant "upgrades" the house at her cost can lead to legal issues down the road then I am not so OK with it (situation going sour for some reason).