It's impossible to keep a coin for several years thoughtlessly. You must track the project and be able to analyze the overall trend of the development. You should be able to understand when to get out at the highest price. It's not easy at all. Never give up!
I gues its possible special if the project is really good and have a future, yes it's hard but i know it can happen that we keep a coin in a years, this can be happen if you have a passive income like a job.