You only need the old programs if you want to open an old tax return. I suggest that you save your returns from past years as PDFs, with all worksheets included, so you can look at them with Adobe Reader. Then you can uninstall the old programs. Uninstalling the old programs will not affect the current program. You should keep the programs for the most recent three prior years, i.e. 2013, 2014, and 2015, in case the IRS questions anything for those years or you have to file an amended return for one of those years.
