Should an H-1B worker max out a 401(k) given the uncertainty of staying in the US?

In most cases, yes — the tax break is too valuable to skip, and the money isn't trapped even if you leave. Contributing up to the 2025 limit of $23,500 ($31,000 with the 50-plus catch-up) cuts your current US taxable income, and employer matching is free money. If you eventually return to India, your 401(k) doesn't vanish: you can leave it invested, roll it to an IRA, or withdraw it (with US tax and possibly a 10% early-withdrawal penalty before 59½). Because India has no Social Security totalization agreement with the US, your own retirement savings carry more weight, making the 401(k) even more important. The main caution is liquidity — don't lock up money you'll need for a near-term move. wealthserene.com/tools/retirement-planner can show how contributions grow even over a shorter US stay.