It can be a life changing amount of money but not always in a good way. If you're not careful, your spending expands like a gas to fill all the available volume and you're just marching sideways towards retirement with nothing saved because it's too fun spending money.
RSUs actually help mitigate this a bit, because you're not going to qualify for a giant house/apartment with your RSU money, and most places aren't even vesting monthly so you're more likely to treat them like bonuses, rather than inflate lifestyle.
Not saying it doesn't happen, but it's probably harder than if it was just suddenly getting a giant salary.
