ESPP's are great. Two things to remember with Employee Stock Purchase Plans
There aren't a lot of people that have this opportunity, but I write this for those that do (for those that don't have one at work, they are pretty sweet. It allows you to buy your company's stock, typically at a discount, and depending on the specifics of the plan and market movement, the gains can be massive, but the probability of a loss is almost zero if you sell at the distribution date. It is kind of like playing the market on your company's stock with a guaranteed return (the discount to market), but an opportunity for a lot more upside). Here are the things to remember:
1. As you mentioned, the holding period. My wife had an ESPP when we first got married a long time ago, and I haven't had one since, so I don't remember specifics about the holding period but pretty sure it is longer than a year (I think I know, but don't want to be wrong and distribute wrong info).
2. More importantly, with the longer holding period, you want to make sure it is a good long term holding. If not, you might be better off immediately selling it and using the cash to buy something else. I always ask the question - would I buy this stock today? That is what you are doing when you hold it. You never go broke taking a profit, but if there is a good outlook, there is some sweet tax savings at the end of that rainbow.
C8D, sounds like you have it covered - this is more for other people that have ESPP to make sure they don't donate early.