Hoping to FIRE in the next couple years (f not sooner) at 53ish. Prior to being able to tap my 401k, we are building up our cash stash. In addition to having cash on hand I was thinking while I am still working at a company that offers both a traditional 401k and Roth 401k should I switch my current contribution from the traditional 401k to the Roth 401k? This way after 5 years I would be able to withdraw what I contributed without penalty. Our cash stash should last us 4 - 4.5 years so if I started now and continue to work another year or 2 that $$ in the Roth would be available when we draw down our cash. Thoughts?