Getting it fleshed out isn't actually happening unless they're building a real product in that time. Talking to people is not "getting it fleshed out". Assuming 4 year vesting then you're talking about giving up a full year's salary to work on something that has probably a less than 10% chance of succeeding. You're also going to have expectations of your time that are pretty extreme. If you want to do that, you need to participate in upside beyond what you're investing in the company ($90,000 of foregone wages) so that there's actual upside at at least 5x that. Consider you're investing $90,000 with a 10% chance of getting $450,000. Are you going to get that with 2% when that will be diluted 30% each round? Without double digit equity it's almost sure you won't. Even then you need change of control language and an understanding of share classes.