Without the proper attention, all furniture, whether for use outdoors or indoors, will begin to deteriorate in quality and condition. Something with moving parts, like patio swings and gliders, requires an even higher level of maintenance to keep them looking new. But in the long haul, the time spent will not only save you time in the future, it will also save you money. By preventing problems from the start, you will have fewer problems later on.
Metal
The biggest problem with metal outdoor furniture, not just patio swings and gliders, is rust. Most swings are made from lighter metals like aluminum (otherwise they would be too heavy to swing) that don't rust as easily as some other metals, but it's still a concern. For starters, keep all metal surfaces as dry as possible at all times. Use a towel to dry off swings after it rains or whenever they get wet so that moisture does not stay on the surface for too long. You might even want to cover your swing with a tarp overnight to protect against dew and during rainstorms.
For any spots you notice that begun to oxidize, use sandpaper or a power sander to remove all signs of rust so that it does not spread. You will also need to take into account the metal hardware, which comes not just with metal swings, but also wood and sometimes resin models. Any pieces and parts that are starting to rust or break down need to be replaced immediately prevent damage to the overall structure.
The last thing to remember for metal swings and other furniture with moving parts is to oil joints and hinges so that they don't stick or squeak.
Wood
The classic and most common choice for patio swings and gliders is woods like cedar, teak and pine. To maintain, remember to take into consideration all of the different wooden pieces, including but not limited to the bench itself. This also means the wooden base underneath the glider seat, the decking, the canopy, the wooden connector beams, and/or an overhead beam and framework. Each of these pieces requires the same kind of maintenance. Replace any pieces of wood which have begun to fall apart. You can control the spread of small cracks and splits in the wood by using fine grained sandpaper to get around and underneath the cracked area.
One of the main things you can do to protect all of your wood furniture from rain, snow and UV rays, is to cover pieces with a sealant of some sort. This will also help to better keep the wood's coloration. Use oil, varnish, sealant, paint or combination thereof, like an oil-based varnish a few times per year. Before doing this, make sure that all wood surfaces are clean, dry, smooth and do not have old varnish still on it. This will make the sealant better adhere and look more even. Leftover varnish can easily be sanded off. Once you do this, wipe all sand dust with a rag and use a mild cleaner like Murphy's to wash the wood.
When you think of wooden swings and gliders one often forgets the metal chains which often connect the swing and allow it to move. There are two problems associated with chains: rust and wobble. Chains are often cheap and so are not covered with rust-proof coatings as is the majority of metal hardware. You will need to replace any rusty chains, making sure to buy the same length of chain for each side. Wobble, or tilt of the swing is usually a result of loose bolts and joints. Keeping all parts tight should correct this problem.
Lastly, wooden patio swings and gliders will also need some amount of oiling, much like metal swings. Moving parts need to be coated with something like WD-40 (which also can more easily get into hard to reach spots). These parts include the swing connectors, joints, any hinges, and the glider track that connects the base and bench parts.
