I need some help with installing roms.

[TMAK~Droid]

I am confused about the whole wiping the cache and data. I don't know exactly what cache and data are and that's why I'm confused. Do u have to wipe all data and cache before u switch roms, if not what happens? I am afraid of losing all of my apps and contacts even tho my gmail will restore my contacts how do I know if it has the contacts saved and how would I get my apps back? One more thing, do u have to make more than one backup if u already have one that u r happy with? Thanks for your help.

Can anyone help me out with this? I'm waitin to upgrade to smoked glass 5.0.1 until I learn how upgrade to smoked glass 5.0.1 until I learn how to do it correctly so I would really appriciate it if someone could take a minute and help me out. Thanks.

[KZIWarrior]

In general if you are installing a ROM with the same base (2.0.1 OR 2.1) than you don't need to clear/wipe (and can use the 'update' method). If/when you go to a different base than you should do a complete clear and wipe all data and install via the nandroid method.

IMHO one of the better sources for your future reference:
Root Your Droid

[mikedav1]

Go to your Gmail account online and see your contacts. If they are there, they will be sucked back in.
Your backup should be the latest with any changes you made. You should get another backup app though. Titanium is good. Saves your apps and associated data.
If you are reverting wholesale back to a previous rom, then the nandroid backup will work fine.

[cplus]

allows you an option during install to wipe data while KEEPING your apps. Your contacts will be restored from your Google account. Since those are your only two concerns, you should be just fine. Keep in mind that even though you will keep your apps, you WILL lose your txt history etc..