Siliconized or top-of-the line polyurethane acrylic caulks give paint jobs a smooth, pleasing look. But the benefits aren’t purely aesthetic. Tight joints also prevent air leaks and block water penetration.

Spring for the $7-a-tube polyurethane caulks with 55-year warranties, which will stand up to weather better than 35-year caulks that cost less than $3. The average house requires about seven tubes of caulk.