How do I not die to invades?

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What do I do about enemy junglers that invade me? What's the defense against clearing a buff and then having Yi/Lee/Shaco/Zed/Talon suddenly jump you and kill you? Even if I'm good and healthy I'll start getting low when I start the buff- what's the way to avoid this?

Buy a yellow trinket at the start and place it either in the river or one of the jungle entrances and position yourself on the other jungle entrance to give you vision of any potential lvl 1 invades. You can also ask your teammates guard one of the jungle entrances or drop their wards on them. If you see the enemy invade, simply leave your jungle and start on the other side of the jungle.

Start with wrd trinket, place it where the invader will be coming from, and if you expect an invde, tell your laners to be prepared to assist.

Its not a fix all, but a good starting point is to ward the bush by the buff. Also drag the buff into the bush with you so the opponent can't immediately target you or your buff. Also ping to your team that there is trouble, chances are they will come help for an early kill.

In addition to doing what the others suggested, ask your allies to ward too; either at the buff you aren't starting at, or a defensive one on the side you do. You're not the only one with a free ward.

If you are facing a jungler who has strong counterjungling capabilities, like , you are going to want to buy a ward and extra potions to stay at max health. Return to base early on first back, even if you can clear the entire jungle it's not worth the risk of the enemy jungler popping in on you at low health.