A lot depends on the exact application, but obviously a capacitor used in that way is one easy way to save things when power fails. Likewise, a battery backed RTC (it could even be the PIC, removing the need for the large capacitor used to save as the power goes off) is essential, but again it depends entirely on the application - it would be VERY easy to get well in excess of a years battery life using just a PIC to do the RTC, depending what else (if anything) the battery is doing.