It is great fun to watch as many turn more yellow at this time of year. It's also fun to watch them drop all of their petals at once - maybe the true meaning of "fall". They'll look fine in a vase one minute and the next you spot all the fallen petals on the table or countertop.
All the digging, cleaning, separating, drying, labeling and storing for winter is definitely not fun and normally it's the worst weather day (or two) when it gets done but that's when we have to remember we had three to four months of glorious blooms from them. They're well worth the work and buying them from any big box store, at 4 for $10.00, makes it so easy.
In early May I bought a few of the tiny border dahlias (along with annual geraniums and alyssum) and they were perfect from May onwards.