Cradle of Vitality
Enchantment
Whenever you gain life, you may pay 
. If you do, put a +1/+1 counter on target creature for each 1 life you gained.
Naya's trees grow tall and sturdy. Their foliage intertwines to form dewcups, rainwater pools where the elves gather to celebrate life.
Trevor Hairsine
Commander 2013 (C13)
• #7Rulings
If multiple creatures you control with lifelink deal damage simultaneously, each instance is a single life-gain event and the ability will trigger separately for each of them.
(wotc • 2014-02-01)
You choose a target when the ability triggers. You don’t choose whether to pay {1}{W} until the ability resolves.
(wotc • 2008-10-01)
Cradle of Vitality triggers just once for each life-gaining event, whether it’s 1 life from Deathgreeter or 8 life from Soul’s Grace. You pay the cost just once, but the targeted creature will get a number of counters equal to the amount of life you gained.
(wotc • 2008-10-01)
Rulings
If multiple creatures you control with lifelink deal damage simultaneously, each instance is a single life-gain event and the ability will trigger separately for each of them.
(wotc • 2014-02-01)
You choose a target when the ability triggers. You don’t choose whether to pay {1}{W} until the ability resolves.
(wotc • 2008-10-01)
Cradle of Vitality triggers just once for each life-gaining event, whether it’s 1 life from Deathgreeter or 8 life from Soul’s Grace. You pay the cost just once, but the targeted creature will get a number of counters equal to the amount of life you gained.
(wotc • 2008-10-01)