“What happens to my 401(k) if I leave?”

Your own contributions are always yours — 100%, from day one, no matter when or why you leave. The employer match is where it gets more nuanced, because of something called vesting.

Vesting is a schedule that determines how much of the employer's contributions you keep if you leave. Some companies vest immediately (you keep everything right away). Others use a schedule — for example, 20% per year over five years. Leave in year two of a schedule like that, and you might keep only a portion of what your employer put in.

Before you give notice anywhere, it's worth checking your vesting date. People have left weeks before a vesting milestone without knowing, and that timing can be worth real money. Your plan's website or HR can tell you exactly where you stand.