You should almost definitely sell all your RSUs immediately when they vest.
Holding your vested RSUs is precisely the same as taking your bi-weekly paycheck (i.e. your salary) and using 100% of it to buy your company’s stock.Source
If you still don’t believe me, it may be because you think (like I did until recently) that you’ll avoid taxes by holding the shares for at least a year. Wrong. That only applies to capital gain income, and you’ll have exactly zero capital gain if you sell it immediately. There is no tax benefit to holding vested RSUs at all.
I didn’t understand that until recently, so this is me trying to save someone else before it’s too late.