My mother very successfully used the original tubers she started off with,for over 30 years!! The first signs of buds probably won't begin to appear until at least April/May depending on how warm the area is they are being stored in. It could also be as late as June,because,the tubers seemed to take longer to bud once they were older. As long as they have been stored in a dry environment,don't worry about them,they'll come on when they're good and ready. Good luck