To Buy or Not To Buy... Second Hand...

The lens on my Pentax MZ-5 seems to have packed it in (my poor baby! 7 years we've spent together!). To tide me over until I can get something better, I've been considering buying a second hand lens for one of the old cameras I was given, a Nikon f801 which goes up to an incredible shutter speed of 1/8000. Here's a helpful article I found.