>>16607330
Split sets rarely need an update, except when they manage to get a better quality dump or dump one of the chips that haven't been dumped yet. The downside is you end up with a bunch of bios files filling your romlist, and if you want to play a specific version of a game you need the clone to go with the parent ROM, which can get annoying fast. Updating a split romset means just adding all the new .zip's to your folder, which will be anywhere from 20-40 per new version.
Merged sets will have ROMs that need an update every single version. This is because it has all the clones, and most of the updates are new clones being added to the collection. If you want to play a different version of the game, you just rename the .zip file to the version of the game you want. Since merged ROMs have every clone, I gotta update every game with a new clone. 99/100 games don't NEED the update to work, I just try to keep the set up-to-date on clones. Updating a merged romset means overwriting the current merged ROMs with the new .zip's, usually about 10-20 ROMs per new version.
MAME is all about the accuracy, so whenever they get another chip dumped and added to a parent ROM, they usually rush to get that chip emulated as part of emulating the game. Which is why older dumps(ROMs from earlier versions of MAME) usually spit up an error about missing ROMs when trying to use them with recent versions of MAME. So you can either update with every single version to stay current(mame roms sooner, pleasuredome sets), or you can take the lazy way out like me and only update when something comes along that makes it worth the time to update, like the GUI improvements back in 0.18X, SF Rush 2049 being added in 0.206, or Akka Arrh in 0.209.
>>16607207
Yep, that's me. Curated merged MAME set since 0.170, condensed console sets started back in march.