I'm 67 and some days feel teh same way - but we must not look at it negatively - we have so much yet to give, and we may outlive many - I will not quit - and please don't anyone else quit - let's see how many of us can die with our quilts in the finishing process on our laps as we do what we enjoy doing most... quilting!!! Don't give up!!!
Life is short so let's make the most of it while we are here; buy enough fabric for the quilt you are working on and then do it over again - if it makes you feel better. I pick up fabric at thrift shops and garage sales, so Im not spending overly much and don't have to feel too guilty about spending too much, and yet I have beautiful quilts from these sources...