you might remember that a while back I asked for input on this. Well, I went ahead. I had it done at the dentist and it cost £400 for made to measure trays and bleach. I am pleased.
My teeth will never be white-white- but on the scale she showed me, my teeth have gone from almost the darkest shade to mid-way light. I am still toppping up and using the bleach once a week or so until I get them as light as they can go.
so, if you are thinking of it, I'd say go for it! My teeth are not perfect and I am still toying with having a brace, but having a whiter smile helps me. I have also started noticing how ageing it is on older people- 45+ - to have stained teeth.