LOL! Those gauges bring back a lot of memories. Expect that car to last at least another 100,000 miles - mine did. I'm surprised you have a tach in a DL, though - what year did that start? I've been very seriously looking around for a 240 GLT (the turbo version, for non-Volvo people) for a beater/sleeper, but they're like hen's teeth here in MD. And Volvo parts are SO damned expensive.
The whole reason I got into cars was because the brake job on that 240 DL I had was upwards of $400... and I was like "WHY?! Why couldn't I do this myself?" So then I learned how cars work, and started doing my own maintenance, and then got into improving various aspects of it... then switched to Hondas after the disastrous 740 Turbo experience... and here I am!
But beater Volvos are great, nevertheless.