It's a personal decision and can go either way, and depends on your cash flow and risk tolerance, and goals.
There are many ways to look at it, and the financial aspects aren't always the most important ones. If you have higher debt (credit card, etc) you probably want to pay those off first.
You may want to have ready cash available (stocks, ETFs, etc can be sold) - but once you put money back into your mortgage it can be hard to get it back out (HELOCs can affect this).
You may find you're not good with savings, and paying extra "forces" you to save (people do this with taxes all the time, preferring to get a large refund as a "windfall" vs having some amount of money extra each paycheck).
And it can all change AGAIN from a cash flow perspective - if you have a few years left on a ten year mortgage paying it down faster gets you to the point where you have no mortgage payment faster - that may not matter to you as much if you're 29 years left on a 30 year mortgage.
Also paying down debt is a certainty, but ETF returns could do anything (we have had ten year periods of negative returns in the past). Conversely, inflation makes your debt load lesser, assuming your income inflates at some point.
There are many ways to look at it, and the financial aspects aren't always the most important ones. If you have higher debt (credit card, etc) you probably want to pay those off first.
You may want to have ready cash available (stocks, ETFs, etc can be sold) - but once you put money back into your mortgage it can be hard to get it back out (HELOCs can affect this).
You may find you're not good with savings, and paying extra "forces" you to save (people do this with taxes all the time, preferring to get a large refund as a "windfall" vs having some amount of money extra each paycheck).
And it can all change AGAIN from a cash flow perspective - if you have a few years left on a ten year mortgage paying it down faster gets you to the point where you have no mortgage payment faster - that may not matter to you as much if you're 29 years left on a 30 year mortgage.
Also paying down debt is a certainty, but ETF returns could do anything (we have had ten year periods of negative returns in the past). Conversely, inflation makes your debt load lesser, assuming your income inflates at some point.