late 20s - internal bleaching again or crown? (Photo)

I had internal bleaching on my front tooth around 4 years ago, but it has got much darker again. My dentist said after my last internal whitening that my tooth would probably be too weak to repeat the process again and I would likely need a crown. I am in my late 20s and wondering if I should try the internal bleaching again (last time it had some impact but it was not drastic) or whether I would be better now opting for a crown to protect the tooth?