When was it built?

This early wiring uses ceramic knobs and tubes, has no ground wire, and its insulation gets brittle with age. It was never meant for today's appliance loads.

What to do. Look in the attic or basement for wires on white ceramic knobs. If you see any, have a licensed electrician check whether it's still live and how much of the house it feeds.

Fuses work, but a lot of old boxes are small for modern use. People sometimes swap in a bigger fuse to stop it blowing, which can let wires overheat.

What to do. Replace a blown fuse only with the same rating printed on the old one. Ask an electrician about upgrading the panel if fuses blow often.

Plaster over wood strips is strong, but it cracks as the house moves and can let go of the lath behind it. Heavy shelves need the right anchors.

What to do. Patch hairline cracks with a plaster or joint compound repair. If a section bulges or sounds hollow and loose when you press it, get a plaster pro to look before it falls.

Homes built before 1978 may have lead paint, and a 1920s house very likely has some under newer coats. Dust from sanding or scraping it is the danger.

What to do. Don't sand or scrape until you test. Use an EPA-recognized lead test kit or hire a certified inspector, and follow EPA lead-safe practices for any work.

Galvanized steel supply pipes rust from the inside, which slowly cuts water pressure and can stain the water. Old cast iron drains can crack or rust through.

What to do. Notice low pressure, rusty water, or slow drains in more than one spot. Have a plumber camera the drains and quote on replacing old supply lines.

Galvanized pipe was common in homes built before about 1960. It rusts from the inside, so pressure drops a little every year.

What to do. Scratch a pipe near the water heater: dull gray that a magnet sticks to is likely galvanized. Get a plumber to quote on replacing it before it leaks.

Two-prong outlets have no ground wire. Swapping in a three-prong outlet without a ground makes it look safer than it is.

What to do. Leave them as they are for now and don't use cheater adapters on big appliances. Have an electrician add grounding or GFCI protection, with the power off at the breaker.

Asbestos was used in some vinyl floor tiles (often 9 x 9 in squares), pipe insulation, and other materials into the 1980s. It's mostly a risk when it's broken or disturbed.

What to do. Leave it alone if it's intact. Get it tested by a licensed asbestos professional before you sand, cut, or pull it up.

Paint in homes built before 1978 may contain lead, and 1950s homes often do. Chipping paint and sanding dust are the main ways people get exposed.

What to do. Test before any sanding or scraping. Follow EPA lead-safe practices, or hire an EPA-certified renovator.

Many 1950s homes were wired for far less power than a modern kitchen uses. An undersized panel can trip or blow often.

What to do. Write down when fuses blow or breakers trip and what was running. Have an electrician check whether the panel and service fit how you live now.

Some homes built from about 1965 to 1973 used aluminum wire for outlets and switches. Its connections can loosen and overheat over time.

What to do. Look for "AL" or "ALUMINUM" printed on wire jackets in the panel or attic, without opening anything. If you find it, have an electrician repair the connections with approved methods.

These panel brands have known problems, including breakers that may not trip when they should. They were common in homes from this era.

What to do. Read the brand name on your panel door or label. If it says Federal Pacific, FPE, Stab-Lok, or Zinsco, book an electrician to evaluate it.

Textured ceilings from this era sometimes contain asbestos. Scraping them sends fibers into the air.

What to do. Don't scrape, sand, or drill into it until it's tested. A licensed asbestos professional can sample it and tell you your options.

Lead paint was banned for homes in 1978, so anything built before then may have it under newer coats. Windows, doors, and trim are common spots.

What to do. Test before you sand or scrape. Use EPA lead-safe practices or hire an EPA-certified renovator.

Polybutylene, a gray or sometimes blue plastic pipe, was installed from about 1978 to 1995. It can get brittle and crack from the inside, often without warning.

What to do. Check where water lines come out of walls, near the water heater, and at the main shutoff. If you see "PB" pipe, get a plumber to quote on replacing it.

Asbestos could still turn up in some popcorn ceilings, vinyl flooring, and pipe insulation into the 1980s. It's mostly a risk when disturbed.

What to do. Leave intact materials alone. Have them tested before any remodel that cuts, sands, or tears them out.

Some homes from the early 1980s still have Federal Pacific or Zinsco panels. Both brands have known problems.

What to do. Read the brand on your panel label. If you see either name, have an electrician evaluate it.

GFCI outlets (the ones with test and reset buttons) cut power fast if something gets wet. Older homes often have fewer than today's codes call for near water.

What to do. Press test, then reset, on any GFCI outlets you have, once a month. Ask an electrician to add them in kitchens, bathrooms, garages, and outside.

Polybutylene was installed until about 1995. Even pipe that hasn't leaked yet can crack without warning as it ages.

What to do. Look for gray plastic pipe stamped "PB" near the water heater or main shutoff. If you find it, get a plumber's quote to replace it.

Many asphalt shingle roofs last about 20 to 30 years. If yours is original, it's near or past that.

What to do. Look from the ground with binoculars for curling, cracked, or missing shingles. Have a roofer inspect it rather than climbing up yourself.

Furnaces and AC units often last about 15 to 20 years. An original system is living on borrowed time.

What to do. Change the filter on schedule and listen for new noises. Book a yearly service visit, and start budgeting if the unit is past 15 years.

Double-pane windows have a seal between the glass. When it fails, you'll see fog or haze between the panes that you can't wipe off.

What to do. Check each window on a cool morning. A failed pane can often be replaced by itself, so ask a window shop before you price whole new windows.

Many asphalt shingle roofs last about 20 to 30 years, and less in hot or stormy places. An original roof on a 2000s house is getting close.

What to do. Scan it from the ground for missing or curling shingles. Check the attic after heavy rain for stains, and have a roofer inspect it.

Tank water heaters often last about 8 to 12 years. If yours came with the house, it's probably past that.

What to do. Find the date on the label on the tank. If it's over 10 years old or you see rust or drips at the base, have a plumber replace it, especially if it's gas.

Furnaces, heat pumps, and AC units often last about 15 to 20 years. Original equipment is reaching that range now.

What to do. Change the filter on schedule. Get a yearly tune-up, and start saving before it quits on the hottest day of the year.

Double-pane window seals wear out with sun and time. Fog between the panes means the seal has failed.

What to do. Walk around on a cool morning and look for haze between the glass. Often only the glass unit needs replacing, so ask for that quote first.

Rubber washer hoses bulge and crack as they age, and a burst one can flood a room fast. Many manufacturers suggest replacing them about every 5 years.

What to do. Pull the washer out and look for bulges or cracks. Swap them for braided stainless hoses, with the water valves turned off first.