How long you can make-do with a given GPU depends heavily on what games you want to play and how much/little graphics detail you are willing to give up to stretch your GPU for a while longer.
I personally don't care all that much for graphics in most games I play as long as they don't look glitchy and ended up stretching my HD5770 for the better part of seven years before upgrading to a 1050.
So, depending on your needs and expectations, the 1060 can be anywhere from already obsolete or irrelevant before it even launched to going to be more than good enough for the foreseeable future.