Bookmarks sere just tiny fragments of text. They are trivial to synchronize. Address books, calendars and filters are rather more complex. Some users address this by not doing it. They use Portable Thunderbird, on a usb memory stick and carry their whole Thunderbird around with them. This doesn't work if, like me, you use a mix of operating systems. Some do it by copying their whole profile from one machine to another. I guess it usually involves a lot of copying which I wouldn't have the patience for. Again, it won't work on a mix of operating systems I rely on cloud resources. I sync my data to a service. I use Dropbox, Google Calendar and Google Contacts. Filters are stored in simple text files and these could in principle be ported from one machine another. But you'd have to make sure your folder systems are consistent. If the filter mechanism finds that a filter uses a folder that it can't find then it will disable that filter. If you're using yet another cloud-based system, IMAP, then you will have consistent folder systems and so your filters should be happy.