yes, I've I've freely mentioned multiple places (not trying to deceive anyone), I use Timeriffic

my weekday schedule is

overnight - airplane mode (the phone is downstairs out of earshot anyway.. why burn radio power when I'd never answer anyway)
6:30am - exit airplane mode
7:30am - enable bluetooth for the drive to work
8:30am - disable bluetooth, and set ringer to vibrate (quiet at work)
4:30pm - enable bluetooth for the drive home, set ringer back for normal
6pm - disable bluetooth
rinse, wash, repeat

and then I have the powerbar(?) widget on my homescreen to enable anything I want outside those hours with a single click.

this is a setup I used with previous phones where I really needed the extra battery time, so I carried it forward when I upgraded to the Sensation, and while I can't say I "need" it, it "costs" me nothing, and I get some "free" extra battery hours as a result. For me, its a no-brainer.

Regardless of the power savings, I'd be using Timeriffic (or any of the many other equivalent utilities.. I'm not trying to shill for timeriffic), to adjust the ringer during work hours and to enable BT during the hours I'm most likely to be in the car.

For those who would not want to put the phone in airplane mode while they sleep, the phone "slept" 3 nights during the graph I posted, for ~7 hours each night, so you can deduct 21 hours from the 2D19H burn time ... which would put me back at just under 2 days, but still having >20% battery left.