this is a genuine suggestion. but I am not a tax professional. use your own discretion.
here's a tip in case it becomes relevant: as soon as you find out you're laid off, update your W4 to "exempt". the company will pay you a lump sum of $x as severance, but the government will tax you as though that amt were a regular pay check. so instead of your regular taxes, they'll take like 50%. if you change your tax status to exempt, they won't. then just look at your most recent pay stub to find out how much tax you normally pay, multiply that by the number of pay periods you got, and set that amt aside for tax time. (ex., if you get 8 weeks' severance, that's 4 pay periods. if you pay $100 in tax per pay stub, put aside $400.)
I happened to know about it because it happened to my brother. he changed it to like 10 dependents, but it still wasn't enough. he was told he should have changed it to exempt, but nobody told him that until AFTER they gobbled up his severance.