When to frag out...

Yes. Back to the subject of video games.

I think that there are few things so embarrassing in a combat game, as dieing with grenades in your inventory. Aside from being sniped or spawn camped you have no excuse for this travesty. You have all the wonderful orbs of death that you COULD have casted in the general direction of your foe (s). You would be surprised at how many chance kills you can get from this. I will include a video of some good ones at the end of this post.
Within the first 20 seconds of spawning into a zone were there/could be enemy presence within throwing range you should unleash your grenades immediately. There are exceptions to this of course. If you are not trying to reveal your situation then you should only throw when doing so does not give you away. If you happen to sea an enemy the FIRST thing you should do if he is NOT shooting at you is to start throwing. Sometimes even if they are gunning for you the best thing is to hope for a kill from the grave. The WORST mindset is that you are saving your explosives up for a good easy kill. You will not usually come across a good easy kill. Your grenades are there to make a hard opponent a little easier.
The purpose of a grenade is not only to blow people/vehicles up. They can be used to defend a position for an EXTREMELY short time. If someone sees your grenade fly into a room they will usually not enter the room until they see/hear it blow up. Thus for the duration of the time that they are waiting the position is being held by the grenade. you can use this to funnel and direct your opponents into going were you want them to go.

NOTE: There is some kinda annoying/fuzzy music playing in the background of this video. Turn down your speakers now if you have a reason to.