I rarely keep mothers. I grow a few extra plants more than I plan on flowering. When it's time to flower, I take the extra plants and clone them, and take a few extra clones to repeat the process. No loss in vigor unless it's grower error. If you see your plant losing vigor, put it out in the sun for a day or two. For some reason this helps, the sun kick starts the plants immune system. But the genetics are always there and stay the same, unless you have like a 20 thousand year old clone that mutated some how haha