My experience with Nair:
On Tuesday (4 days ago) I was getting stubble on my chest, so decided to try out the bottle of Nair + lotion that I'd gotten "just for this occasion!" LOL
I read the instructions, it said apply it thickly, wait 3 minutes, wipe off a sample, if the hair comes off, wipe off the rest...if it doesn't, keep it on another 3 minutes, but no more than 10.
I split the difference, made it 5. At first it just felt like any other lotion. By 3 mins, it was starting to sting a little. At 5, I wiped it off, and most of the hairs came off with it.
I jumped into the shower, rinsed, soaped, scrubbed (lightly! ouch ouch ouch) and realized I'd just been chemical burned. (I've had those before, so I know what it feels like)
That evening my chest (especially the nipples) felt as if it had a medium-strength sunburn, and there was no relief for it. Next day, my shirt kept renewing the sense that I'd been sunburned...by the next evening (Wednesday, about 36 hours later), my chest was a lot less painful, but the nips were red and irritated.
Next morning (48 hours later) most of the pain/redness was gone. Today (Friday, 4 1/2 days later) there's no pain, no redness, and the hair is still gone. Not even stubble yet.
Would I use it again? Maybe, but probably not. There are times a razor isn't available (at least, not a sharp one), and Nair does seem to work. For me, 5 minutes may be too much on the chest, but waxing is no longer an option for me there. The stink is bad, though. Yuk!
I'll try to remember to update this when I start getting stubble again...see how long it lasts.