Investors are doubling down on the market's staples.

The Consumer Staples Select Sector SPDR Fund, widely known by its ticker, XLP, hit a new 52-week high on Monday, a more than 18% climb from its lows in December. The move was fueled by stronger-than-expected quarterly earnings from Kleenex parent Kimberly-Clark, which could set the rest of the group up for a good week of reporting.

Still, Dave Nadig, managing director of ETF.com, is encouraging investors to be careful with this group, which many see as a safe haven in the stock market.

"I think 'new highs' is a relative term," he said Monday on CNBC's "ETF Edge." "We're only up 12, 13% in this space. This is far from the high-flying segment."

And with industry giants Procter & Gamble and Coca-Cola — which account for more than 25% of the XLP — reporting later this week, that's "a lot of concentration" to discount at the moment, Nadig said.

Even so, Nadig still sees opportunities, particularly in U.S.-based consumer staples ETFs.

"I'm still a believer that we're in a global slowdown environment, [so] I'd rather stick to the U.S.," he said. "I think it's a little more understandable, a little more controllable. I would go with equal-weight here because I think that that concentration … could help you. If P&G really blows the doors off, you'll want that exposure. But I think, long term ... the smaller names are doing as well as the bigger names. Why not give yourself a little bit of short-term diversification?"

Alternative plays with exposure to the automotive space could also serve investors well, Nadig said.

But if you ask ETF expert Reggie Brown, who is senior managing director of Cantor Fitzgerald's ETF group, investors' moves this earnings season will ultimately boil down to two factors.

"Investors love earnings and outcomes," he said in the same "ETF Edge" interview. "So I think you're seeing a drive into the sector based on performance of the underlying companies and, as you know, ETFs represent performance of underlying stocks. So you're seeing investors want to have exposure."

The XLP flattened after reaching its 52-week high in Monday's trading session, hovering in the $56 range. The Invesco S&P 500 Equal Weight Consumer Staples ETF, its equally weighted counterpart, also hit a 52-week high.