Yeah I think the standard is to sell some percentage of the RSU grant each time there is a distribution (to cover the taxes of getting it as income).

Unfortunately this is usually insufficient in most companies and one will likely still owe a big chunk of change to the IRS each year as a result.

One can ask for extra withholding, but it's a bit tricky to figure out until one has worked for a given company / comp level for a given year.