Does it ever just hit you that one day even the simplest of tasks may become impossible for you?

I was clipping toenails the other night(excuse the example) and for some weird reason it hit me that at some point in my life I will probably not be able to do that due to old age and everything that accompanies it. Things we now do at the wink of an eye, quick movements, running around to get bills paid and so much more may at some moment become a nightmare! Do you ever think about it or do you push such thoughts as far back as possible?