Is 10 year old unopened paint still good?

Ten year old unopened paint is generally not still good and should be tested before use, as most paint has shelf life of 2 to 10 years depending on type and storage conditions, even unopened. Latex water-based paint unopened stored in cool dry place typically lasts up to 10 years, but often goes bad after 5 to 7 years, with pigments settling, binding agents separating, and bacteria growth causing sour smell. Oil-based paint unopened can last 10 to 15 years because solvents preserve it longer, but it may thicken and skin over. Signs 10 year old paint is bad include strong sour or rancid smell, lumps that do not stir out after thorough mixing, inability to blend separated liquid after stirring, and dried solid mass. To test, open can and stir thoroughly for 5 minutes; if paint mixes to smooth consistency similar to new paint and smells normal, it may be usable for low visibility areas like garage or closet, but do test patch and check drying. Even if it looks okay, old paint may have poor adhesion, coverage, and color accuracy. Manufacturers recommend not using paint over 10 years old for critical jobs, as warranty expired. Storing paint upside down, in climate controlled area 50 to 77 degrees, extends life. If can was frozen, thawed, or stored in hot shed, it is likely bad. For best results, buy new paint for main rooms. Dispose of bad paint at hazardous waste facility.