In PVE, I won't rez people who die by their own hand. Stand in fire? You can rez yourself. That is unless it was an honest mistake and not their usual behavior. That or when we need them up to finish the fight.

In PVP, I rez when there is no forward camp nearby. If there is a FC within reasonable distance, I don't feel it is worth it.

So generally, I am more than willing to rez people, whether I know them or not. My soul gems aren't as important as good teamwork and everyone having a good time. Unfortunately, people rarely return the favor. I see people in PVP run right by me all the time even after a fight has ended. Sometimes even people I had just revived seconds prior.

I have no problem with using soul gems on friendly people in my group, random or not, if i have them.

Only time i don't revive is if i don't have soul gems of the appropiate* level. Or if my group is very hostile. But havent experienced that so far. Or simply if im out of them.

Not when im leveling . But in pve groups and pvp groups? everytime .

In pvp , I hate when my keep is under attack, the keep is about to fall ..and people dont resurrect the dead !! thats why I always use my soulgems when I see a dead people.
Its not like the soulgems cost 1k each ...xD

Always make sure i have a full stack, always rez any dead.

I play solo or with my girlfriend and don't do much in terms of group content.

I amass a whole ton of Soul Gems that I don't otherwise use. I have 149 filled Grand Soul Gems in my bag at present.

I'll toss someone a res if I see they need one, but I tend to favour doing so more in PvP.

I only tend to rezz low levels (under 50) in cyrodil, as there horses are crap, so takes poor buggers ages to run back.

or I will rezz sombody I see soloing outside the zerg.

I love to rezz people even when solo questing, although I always keep one soul gem for myself.
Why I love rezzing people? I'm not certain... I think for me it's a mix of aiding people who - evidently - are in trouble, as well as having the power to restore life

After farming chests for a while, I have almost 200 empty soul gems, and about 147 full ones.

If I see someone who dies, not just laying dead, I will offer them a rez.

In PvE zones I wont rez random dead ppl I come across. Nothing there is worth my soulgems.
In PvE grouped content I will spend some of my gems if necessary (during ongoing battles) - however, I find it extremely rude if someone groups for an ini but does not bring his own gem supply and expects a free rez after a battle is won.

In C I would rez if there is a reasonable chance that the ongoing battle could still be won; but I usually wont rez randoms I did not see die or the fallout if two zergs collide; that's just a waste of gems (and time).

In my group or in pvp? sure. In open world pve? hell no.

To my mind it's paying it forward.

I usually have a half dozen charged gems ( thanks, 10% chance to steal souls! ) or more and don't often come across people who actually need a rez so it's not really an inconvenience.

It's more like paying to not be alone. It also help creating attrition for long duration fighting.
Kill more enemies, and you get them to waste more time/gems/forward camps.

It also encourages positive interaction between players.
"hey that dude revived me, cool"

It's just touchy feely friendship is magical, but it works. It helps creating the mmo feeling far more than being able to akways revive on our own.

I use them for group mostly and sometimes for non-group members. I always buy a load of empty ones and when in need i charge them during PvP.

I see it as just helping my fellow player in trouble out. I'm not stingy, so feel free to die around me, people!