It's common to have big bar lust, beyond what is really necessary. Somehow it just seems like a really long bar or two would make our life better somehow. I speak from experience here.
Something to think about when gettin long bars for those "occasional" big trees: Many will end up with a bigger saw eventually, so make sure you buy a mount that will work on your bigger saw.
For example, I have long bars for my 066 that I probably will never use again given I have a 3120 and 880. I'll keep them in case I end up with a 771 or whatever stihl calls the rumored 100+cc saw....
The nice thing about Dolmars and huskies is that all the large mount systems are the same. My 7900s, 371, 395, 3120 all take the same bar. For the 880 I had to buy it's own set of bars....Not so bad for my ES bars, but kind of painful with a 50" Cannon.