I'd pretty much just gotten started on JA2 1.12 when I decided to go all out and install the 1.13 patch to take care of the crashes I was getting.

1.12 always crashed when I quit the game, and one other time when I had set off some dynamite, but now 1.13 crashes randomly for no apparent reason, but doesn't crash on quit.

Anyone know of any patches or mods that make the game more stable, or is it pretty much a case of 'Save Early, Save Often'?

I always get the crash on exit but it doesn't bother me. Other than that the game is a flawed gem and ALT S is your best friend as it sometimes has fits of instability. It will play fine for me for mission after mission and then suddenly decide to have a stroppy fit and even crash when all I try to do is advance the time.

If it always crashes at the same minute (in-game time), the problem can usually be circumvented by switching into tactical view and letting that minute pass there. Other than one of those and the "quit crash", I think I have had only one crash during my first and so far only (but lengthy) playthrough with the GOG version.

I did one playthrough with 1.13 and can't recall any crashes at all. The version I had installed was "JA2 1.13 3111 exe SVN@1183 Full" (single click installer). I'm not suggesting the newer builds are unstable, but this version worked really well for me.

Yeah, that's the same file I used to upgrade to 1.13 and I've been having issues still. About 1 crash every 2 hours on average. The crashes don't seem to be related to anything in particular.