Is teeth whitening worth the cost and hassle?

People's experiences vary a lot. When my group of friends were going through the phase of life with lots of weddings (their own and/or being in the bridal party of others or even just guests), a lot of them tried tooth whitening. I saw everything from great results after 2 weeks of a decently strong otc product, and horror stories from professional dentist treatments and everything in between. Worst was my friend who had been using a 5% hydrogen peroxide otc tooth paste plus the odd box of whitening strips a couple of times a year with great results (model material tooth colour). Spent no more than a hundred bucks a year on it, great results and very little sensitivity. Her mother in law who worked as a dental hygienist constantly told her she was being cheap and otc stuff was ineffective and would damage her enamel etc. Pressured her to get it done at the dentist claiming the results she'd had from on office treatment was much better (no it really wasnt). She finally caved and did it mostly to shut her MIL up. Despite going to one of the so called leading dentists, her results were so so. No discernible difference from her usual routine, but intense sensitivity and hundreds of dollars. Plus the dentist eas a judgemental a....... who judged her for otc products and then failed to do a better job.