It'd certainly be simpler if I didn't have to remember to do it. Thing is I dont leave my machine on - some days I turn it on and off several times during the day - just depends on what I'm dong at the time - so scheduling back-ups and clones etc still needs intervention or at least very regular habits I guess. Just a personal thing.
On other hand if there's catastrophic failure in either drive in the fusion volume it'd be nice to have another internal boot volume. Without boot disk I'm not sure can Lion or mLion find an external boot volume?
You could consider leaving your Mac on all the time, or only shut down at the end of the day if you must. Just configure it to go to sleep after a reasonable interval of idle time.
If you have a bus-powered external USB drive, just leave it plugged in all the time. Time Machine will do a backup a few minutes after you start (or wake up) your system, and every hour or so while it is running.
Your internal Lion (or Mountain Lion) disk should have a recovery partition. You can boot that and restore from an external Time Machine drive if you need to, provided the whole internal disk doesn't fail. If you have an internet connection, you can also boot over the network to recover if necessary. You can also make a recovery disk on a USB flash drive; you need to do this in advance, while you still have a working disk in the system.
If you're serious about recovering your system easily, you should TEST these recovery methods now, so you know how they work and confirm that things are set up correctly. If this is your only computer, you should find AND PRINT the appropriate recovery instructions from Apple's support pages in advance, since you won't be able to get them if you can't boot.
Everything in the previous two paragraphs is to make your life easier if you ever need to recover the system -- but it only matters if you have a copy of your data! The MOST important step is to get your Time Machine drive connected and set up, and leave it that way! TODAY!! IMMEDIATELY!! FOREVER!!