If she's well-built and you look after her - in our climate she'll outlast you no problem. The better TS16's (TS18's and 21's) have the seams between plywood sheets fibreglass taped and faired over.
Apart from their seaworthiness and ease of handling, two of the best things about these boats is:
(a) the entire length of the boat is used - no wasted space.
(b) the boat's strength (and there is a lot of it!) is in the hull, not the internal fittings - so if you don't like how she's laid out inside, feel free to change it.
If you ever need repairs done, there's an ex-TS16 owner on the Hartley TS18-21 Committee who specialises in fixing and modifying Hartley TS's. If you need to, PM me and I'll put you onto him.
Enjoy!!.. If you're up to it, the TS18-21 YC hold a cruise on the Gippsland Lakes over Christmas (come and go as you like) ... and if you're ever racing with the Association, look out for Michael Horvath - he'll show you how it's done.