I've only been back a few days, and I've already seen more than one person lose their settings. There's really no excuse for this, if you do it right.
1. Get dropbox. You might also be able to use google drive or some other cloud system - but dropbox is great because it has a hidden (albeit it limited and dumbed down) version control system, meaning that even if you lose your stuff because you accidentally delete it within mudlet AND can't access mudlet's built in backups for some reason, dropbox probably has a hidden older version backup as well.
2. Get a blank package (XML settings file) for mudlet. Either use the package exporter to create your own, or download the one I have attached. If you use the one I attached, don't forget to unzip it.
3. Rename the personal.xml file to whatever you want your personal settings package to be called.
4. Put the XML file into your dropbox folder.
5. In mudlet, go to Toolbox > Module Manager
6. Click 'install' and choose the XML file
7. Check the "don't sync" checkbox (checking it will mean that it DOES sync, which means, changes you make are saved. Yes, this is a bit unintuitive. Just make sure it is checked.
Now, in the script/trigger/alias/keybinding editor, you'll see your package. Put all your settings in here, click save, and every time you do click save, the changes are saved not only to the normal place mudlet keeps backups, but also to that XML file in dropbox.
Never lose your stuff again.
(Also handy if you play from multiple computers).
Lastly - I'm pretty sure this process can be adapted to work for other clients as well.