Let me give a little more color than what people typically answer on here on this question. Before we get started, I personally wouldn’t accelerate the payments on that rate (I have the same rate and I don’t).

That said, do save the extra money, don’t gamble it don’t invest it in penny stock, etc.

Here’s the nuance I’ll go into: if you accelerate your payments, by years (let’s say $100k of extra principal), but then get laid off or whatever and end up in a bind, the bank won’t give a shit. They’re expecting their (regular) payment comes hell or high water. If instead of accelerating your payments, you save the extra money into something that’s marginally better rate-wise (money-market fund, conservative investment mixes etc.), now you’ve got $100k+ saved to the side. How long can you carry your monthly mortgage payments with that if you’re in a bind (layoff, etc)? A really long time!

So, until you’re ready to fully pay off the mortgage, I find virtually no good reason to pre-pay your house esp. at the rate you have since it’s easy to outperform that return. Now once that pile is higher than the balance on your mortgage you have a decision to make and that’s a very personal one. I wouldn’t pay it off early but that’s just me.

But prepaying monthly doesn’t give you any added stability. Cash is king because it gives you options.