DIY watch repair - surprising result

[Pints]

I found an old box a few months back which contained various items from my youth, one of which was the watch I had as a schoolboy. Nothing fancy, just a quartz.

I tried it on and the perished strap promptly snapped. I managed to find a replacement (rather unusual fitting strap) on ebay and ordered a new battery while I was there. Long story short, I ordered a 2nd battery which also seemingly didn't get the watch working.

I'd now spent £5 on a watch which probably wasn't worth a fiver to start with. There was nothing to lose so I opened the back up, gave it a small squirt of WD-40, dried off the excess with a tissue, popped the battery back in and... hey presto! 15-odd years since it was last on my wrist, most of which was spent in a damp garage in a box, and it seems to be ticking away quite nicely (or has done for the last 35 minutes).

So, is this just a brief recovery before the WD-40 stops it ticking forever or should I open up my own watch repair shop.
What do the watch knowledgeables think?

[Pints]

Cheers Glaz. Points noted but since it wasn't really going to work on its own accord, and not worth the repair cost, it seemed a worthwhile effort.

Now 17.19 and it's been running since 8.29. So far so good

If it dies it just gives me a good reason to buy that G-shock I've had my eye on.