[Hero CDMA General] willowmp:
RA-Amon's custom recovery is a must and is vastly more important than a back-up app. RA-Amon's recovery is an actual recovery image, thus as long as your phone boots up to the HTC logo you should be able to access RA-Amon's recovery and thus restore the backup before the phone is even accessing the rom.

Flashing a recovery image is like flashing a rom, but instead of a rom you are flashing a recovery image. Your phone has a stock recovery image on it right now, I don't know the key combo but hold a certain pattern of keys down while turning the phone on and you will enter it. It looks I think like a triangle with an ! in the middle or something. This is sorta useless for us though because I don't think you can really do much with it.

When you flash a recovery img (RA-Amon's) that stock recovery image is just replaced with Amon's. After you do flash the recovery holding the HOME and power button to turn the phone on and continuing to hold it will cause you to enter Amon's recovery, which is a green menu. From this menu you can amke backups/restore them, wipe the data on the phone (factory reset), flash .zips (roms, bootscreens, themes, kernels) and other things.

What you are referring to the writing backup to sd card is called nandroid. Nandroid is an option in the recovery, so yes if you do flash the wrong rom or your phone won't boot up (boot loop or whatever) as long as you can access recovery which is one of the first things loaded when you hit the power button (unless you really do something spectacular like flashing a gsm hero's radio you almost always will be able to get into recovery. don't even touch radios right now, flash the wrong one and your phone won't even turn on/charge. aka your motherboard will be totaled) so you will almost always be able to nandroid recovery your os if something does go wrong.

In short before you do anything flash the recovery.

Now on to your other questions. I have been running the overclocked kernel for one day, but it appears stable and seems to be working good for me. When you flash a kernel you always flash it over a rom, because if you do it the other way the rom will replace the kernel. So yes once you have damagecontrol or another rom that supports that kernel you can simply go into recovery and use flash .zip to flash the kernel over the rom. As always make sure to make a nandroid before doing so.

DamageControl supports apps2sd, and you enable it to use a2sd using the Dconfig app that is included in the rom. It is generally a good idea to partition your sd card whenever you switch between roms unless they say it is fine. You should go ahead and copy over a backup of your sd card to your computer, however you need not format or wipe your sd card when flashing roms. Honestly I don't think you need to partition your sd card again, unless after you flash the rom the os won't boot up all the way or loops/crashes. If it does then partition the sd card and try rebooting the phone and it should fix it.

Also you can format and partition your sd card in recovery under Other.

As for my battery life I have been switching b/w roms and such and I just started using the OC kernel, but with the DamageControl rom back when I only had that flashed my batt life was good.

However I do have 3 batteries and an external battery charger for my phone. Check out the accessories section of this forum, 2 batteries and the charger for 11 bucks from Hong Kong on ebay.

Hope I helped. :)