This week’s lifting of mask requirements on airplanes and, in many parts of the country, on public transportation is a major turning point in the U.S. pandemic response. From now on, it seems, avoiding or minimizing COVID-19 infection will be a personal endeavor, not a societal one.

This is for some people a welcome shift toward normalcy and for others a cause for anxiety and confusion. Many occupy an awkward middle space between not wanting to throw in the towel and also wanting to break free of some restrictions. About 42% of adults in the U.S. have gone back to some but not all of their pre-pandemic activities, according to a Kaiser Family Foundation poll.

As the rules ease, avoiding infection gets harder – especially as more contagious variants circulate and community transmission becomes more difficult to track.

“It feels like we’re being asked to partake in a trust fall,” says Ajay Sethi, an epidemiologist at University of Wisconsin-Madison, referring to the team-building exercise that involves falling backward and counting on others to catch you before you hit the floor. “When is the last time you did a trust fall and enjoyed it?”

Calculating and managing one’s personal risk of COVID in a community might be getting trickier, but it’s still possible. Here are the most straightforward ways to minimize your risk.

Roll up your sleeve

Some obvious advice bears repeating: The best way to protect against COVID-19 is to be vaccinated. COVID fatigue is discouraging some folks who eagerly got their initial shots a year ago from getting their boosters now. But the data is clear that vaccines keep most people out of the hospital and are estimated to have saved 1.1 million lives in the first year they were available. The value of a first booster for at-risk groups is also clear. Beyond lowering the risk of severe disease, scientists have found that it improves the potency and breadth of the memory immune cells so they are better equipped against new variants. Yet only about 30% of people in the U.S. have gotten their first booster, which leaves room for improvement.

Hang onto your mask

Mandates have lifted, but public health experts with whom I’ve spoken are nearly unanimous on the value of wearing masks in situations where people are crowded together indoors. Indeed, the current free-for-all means it makes sense to upgrade your mask to a well-fitting N95 or equivalent.

That includes on airplanes. Yes, planes have excellent air filtration – but only while in flight. The air-flow systems are typically turned off when planes sit at the gate or taxi, and then the risk of virus transmission is high.

People experiencing mask fatigue should remember: Masks need not be an all-or-nothing proposition, says Asaf Bitton, a professor of health care policy at Harvard Medical School. Consider your vaccination status and your surroundings. Going maskless is far less risky in a big box store with high ceilings, fans and an audibly rumbling HVAC system than it is in a packed bus or subway car. Attending a dinner party with friends who have tested negative in a home with windows cracked open and a portable HEPA filter running is safer than sitting elbow-to-elbow with strangers at a restaurant.

In general, it pays to consider the ventilation and filtration of any setting in deciding whether to wear a mask. As I’ve argued before, air hygiene is the most underappreciated way to reduce COVID transmission.

Follow the poop

Data on case numbers has grown less reliable as more people test at home or don’t test at all, but there are other ways to gauge the extent to which COVID is going around. Hospitalization data remain the most reliable indication of an outbreak, but those numbers lag a rise in infections. To see a wave coming, look to wastewater data, which tracks viral RNA levels in sewage.

Everyone who has COVID flushes evidence of their infection down the toilet – evidence that exists even before it would be picked up on a test. That makes wastewater data a good sentinel for rising cases, and a guide to knowing when to be more vigilant about masking and moving your restaurant reservations to the patio.

Sethi also suggests keeping an eye on case data from neighboring communities, which can presage an uptick in your own. He lives in Wisconsin and watches data coming from Michigan and Minnesota, which in the past two years have tracked a few weeks ahead of his state.

Plan vacations with COVID in mind

People who are finally taking a long-delayed and much-needed vacation should also consider the COVID status of their destination, says Neil Maniar, director of Northeastern University’s Master of Public Health in Urban Health Program. Also check out local vaccination rates and mask requirements. If a lot of virus is circulating, perhaps opt to eat only outdoors or take a private tour rather than piling into a bus with strangers.

If you’re traveling to another country, know what happens if you get infected there. How long would you need to quarantine, and where might you do that? As someone who recently caught COVID while in another country, trust me when I say these things happen more often than you might think.

Constantly calculating COVID risk may seem exhausting, but it’s the safest way to navigate a mostly mask-free world.

Lisa Jarvis, the former executive editor of Chemical & Engineering News, writes about biotech, drug discovery and the pharmaceutical industry for Bloomberg Opinion.