Take time now to get your window screens and screen doors in shape. Even tiny holes can allow squadrons of mosquitoes to zoom through.

Screening is available in aluminum or fiberglass. Fiberglass comes in several colors, and it is cheaper than aluminum and more flexible, making it easier to install.But fiberglass is also easily damaged and stretched out of shape. Although stronger than fiberglass, aluminum is subject to corrosion and trickier to install.

Unless you're replacing all of your screening, use the same material currently in place so the repaired screen blends in.

Plugging holes

With care, modern screening will last for years. Accidental holes, however, are just about unavoidable. Make repairs when holes occur before the entire screen has to be replaced.

Here are some tips:

- Plug small holes with a dab of clear nail polish or shellac.

- To patch a larger hole in aluminum, cut a scrap piece 1 inch larger all around than the damaged area. Unravel a few strands of wire from all sides of the patch. Then bend the ends upward. Push them through the screening and fold them flat on the other side.

- To patch fiberglass screening, neatly trim the edges of the damaged area. Cut a patch from a scrap one-half-inch larger all around. Make sure the pattern aligns. Apply a thin bead of clear, all-purpose household cement around the edges of the patch and press it in place. Smooth the glue and blot excess with a rag before it dries.

- Children can't reach the doorknob, so they often stiff-arm the screen on their way out. Inexpensive guards, which you can mount over the screens, are available at home centers and hardware stores.

Replacing screens

Replacement screening is sold in several widths, either by the foot or in rolls of various lengths. Purchase enough material to cover the screen frame with at least a 1-inch overhang on all sides.

On most metal-frame screens, the screening is held in place by a spline that fits into a groove. Some screens have reusable metal splines, but most have vinyl splines that should be replaced if old and stiff.

To get the right size, take a piece of the old spline to the store. Also pick an inexpensive tool called a spline roller.

Remove the old splines with an awl or thin screwdriver. Cut new screening about 1 inch larger than the frame on all sides. Lay it over the frame evenly, aligning a strand of screening with the groove.

Clamp the screening to one short side of the frame. Starting at a corner on the side opposite the clamped side, pull the screening taut and roll the spline into place. Trim excess screening with a utility knife.