Coloring tip: It's a fact. The longer your hair is the older the ends are. Okay no news there. What may be news is that this makes them more porous and open to accepting hair dye. Which is why you want to get to them last if coloring at home. Otherwise they may end up darker than the rest of your strands leaving you with a final result that is well, interesting looking. Just not in a cute and sexy way.
Another thing that's changed from when your mom used to color her grays away under the cover of darkness is the quality of the products available. It's been a long time since anyone has gotten even a whiff of any strong, offensive smelling products in salons. Those have long since disappeared or been replaced by gentler formulations that are free, or mostly free from ammonia, peroxide or other harsher chemicals.