I like lithium batteries for trips due to all the reasons DD mentioned.

Case in point: I borrowed a different depth finder this year. The fishing aficionados I know lead me to believe I could easily do two weeks on a set. Unfortunately, I expect I forgot to turn off the one I borrowed this year on the first night since my $15.00s worth (8 AAs) was dead the next day. It was raining and I didn't know if it was a short or I left the light on or was pinging the moon all night long or all three. Next night my flashlight said all 8 were dead for all intents and purposes.

I did have a total of 8 new AA's with me to power a camera and two flashlights so I went without and tried the depth finder again mid trip. The thing was showing 13 volts a week later and I left it on quite a bit once I hit familiar territory just to get a better feel. Six of the original "dead ones" are still powering my wife's mouse and keyboard longer than the alks that came with. The other two are in my 30 some year old calculator and the last digit is is only slightly dimmer than the rest after a while.

I do like the lithium for trips. Proprietary batteries are a bit of a pain and you would need a solar panel for some things I won't bring. I've never trusted rechargeables even when I know them well. Everything I bring takes some form of single use batts but I start out with rechargeables. The lithiums have a really long shelf-life too.

Master, I've been using that sweet unit for years.  Alkalines run forever in it....any cheapo brand.  It's your use of the backlight that runs 'em dry.  I used my machine alot and I'll wager that 4 extra cheapo AA's in the pack...and you are good for over a week.  I've never had to change batteries once yet on a 5 day trip or less.  And all I ever use is the cheapest blue-light specials.

Was gonna upgrade to the 62...but saw a blowout price on a Colorado I couldn't pass up.

master....do not let me feed you, unless you want to starve.

gotta say I'm having some remorse of not going for the GPS62.  the Colorado looks and seems like an adequate instrument ($100 off due to overstock), but the screen is just not quite as bright as that GPS60 series.