Elissa Sanci

Match an air purifier to your room by its CADR, at least two thirds of the room's square feet on the EPA's chart; true HEPA filters are defined at 0.3 microns.

Fill power measures how much space an ounce of down fills, so a higher number means more loft for the weight; comforter sizes run wider than their mattress.

Buy the duvet insert for your mattress size and the cover to match the insert; go up one size for a tall mattress or more overhang.

Watts only show what a grow light draws; plants use light from 400 to 700 nanometers, measured as PPFD, and leafy greens need far less than fruiting plants.

Pick a litter box your cat can turn around in with low sides to step over, and keep one box per cat plus one extra, spread around the home.

Loft is a pillow's height; side sleepers usually need 3 to 5 inches or more, stomach sleepers under 3, and the fill decides how well that height holds.

Pick a planter big and deep enough for the plant's roots but not much bigger, with a drainage hole; material changes how fast the soil dries.

A swing set needs clear space in front and behind equal to twice the height of its top bar, plus 6 feet on the sides, so an 8-foot set needs 16 feet each way.

Start with the feeding guide on the can, split it into meals by your cat's age, adjust to keep a healthy weight, and refrigerate or toss leftovers.

Measure floor to ceiling and leave at least a foot for the stand and topper; 7 to 7.5 feet is the most common artificial tree height we list.

Soft, medium, medium firm and firm are each maker's own labels for how much a mattress gives; medium firm is the most common label we list.