The answer to 'P-trap replacement frequency' is that P-traps under sinks and in other plumbing fixtures typically last 5-10 years before they may need to be replaced. P-traps are designed to maintain a water seal that prevents sewer gases from entering the home, but over time they can become cracked, clogged, or corroded, requiring replacement.
P-trap replacement is usually a straightforward DIY task, but it's important to turn off the water supply and have the right tools on hand. If you're not comfortable with plumbing work, it's best to call a professional plumber to ensure the job is done properly and safely.