My son reminded me a couple of days ago about the importance of work coming before a reward. It seems to be an age old principle, but it is one that is effective in motivating people to strive to complete a task they accept to take on.
As we drove back from school I asked if he would help me fold the clothes and in turn get a reward of a slice of cake, to this he agreed most willing. When we got home, he asked if he could have the cake right away, and I gave it to him reminding him that when he had eaten it we had to do the chores. I waited for a bit and he did not turn up, I called and he began to give me excuses. After a bit of threatening, he reluctantly carried out his own part of the deal.
It then hit me that the purpose of a reward is to satiate the one that has accomplished a task. It is meant to come after, not before. Rarely do people actually do what they are meant to do if they receive their reward before they do it.
If what you have in your hand is a gift, then by all means give it whenever you like as it is not linked to any sort of performance. However, if what you have is a reward, then it is different and must only be released after the task for which it is earmarked has been properly done. In doing this you are not only preventing disappointment for yourself, but you are providing a source of motivation for another that could help them accomplish their best work yet.