2016-09-20 : You can pay {1} only once each time Durable Handicraft's triggered ability resolves. You can't pay more to put multiple +1/+1 counters on a creature.

2016-09-20 : You don't choose whether to pay {1} until Durable Handicraft's triggered ability is resolving. No player may take actions between the time you choose to pay and the time the creature gets a +1/+1 counter.