Just buy it. I bought the combo as a back up to my t liner. The shaver cuts as close as the t liner unless you modify the t liner. The smoother blew me away. Both are surprisingly heavy for their size. The smoother performed better than the andis smoother and didn’t leave me with razor bumps. Pleasantly surprised would recommend. As to longevity I cannot say. My t liner is about 8 years old. The smoother about a year. So in that regard I cannot comment. But first impressions on these are money well spent.