Hopping in and out of stocks tends to do more harm than good to your portfolio. Fortunately, most of the time, investors are content to sit back and let time do the heavy lifting.

Every now and then, however, an uninterrupted market-wide rally (such as the one we saw in 2017) followed by a couple of major corrections (such as the ones we've seen in 2018) inspires a more active approach. Buying every dip last year was a bulletproof strategy; steering clear of this year's big dips would've left most investors far better off.

But broadly speaking, investors shouldn't embrace that short-term mindset. Buy-and-hold is a time-tested strategy that helps investors avoid trying to time the market (which even experts can't reliably do) and making poor emotional decisions.

With that as a backdrop, here are a dozen stocks to never sell. Many buy-and-holders are looking to reset their portfolios as the new year begins. If you hold any of the stocks, don't stop ... and if you're looking to buy, be ready to commit. Each company has plenty to success that their history of success should continue for years to come. And each operates in an industry that won't go away anytime soon.

3M

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3M (MMM, $198.32) shareholders aren't strangers to prolonged periods of tepid performance. The stock made no net progress whatsoever from late 2003 to late 2012.

But it still was a worthwhile holding during that time. How? 3M's quarterly dividend grew from 33 cents per share at the beginning of that timeframe to 59 cents by the end, and it was never suspended or cut. Better yet, 3M earned more than it dished out during that period; it could afford its payments.

3M is