Size:
Most vintage metal lawn chairs will measure approximately 20-25 inches wide. The retro look often involves wider arms, meaning the overall width will increase even if the seat isn't as large. Because of this, you'll need to make sure you have enough room where you plan to put your chairs. Per Charlotte Moss, a pair of metal lawn chairs will look lovely on your porch, but the effect is quickly lost if they are crammed into a space with an ill-fitting table between them. If the chairs are for your back garden, check you can position them with at least 8-10 inches of space between the chairs and any plants or flowerbeds. This will create a well-spaced look more pleasing to the eye.
Style:
All vintage lawn chairs will have a particular look reminiscent of past eras, but there are varying vintage styles available. Mid-century modern chairs will usually have tapered legs and a sleek look, whereas a 1980s chair is more likely to look like the pool chairs we're used to seeing now due to the ridged backs and wide-set legs. Though the lawn chairs featured all have a vintage style, look at your garden layout or existing outdoor furniture to make sure everything will blend together seamlessly.
Material:
Though your vintage metal lawn chair will obviously be made of metal, Darryl Carter says it's vital to check the type of metal it is constructed from. This is because some metals will wear better than others. A good example of a metal that wears well is steel -- though steel does rust like other metals, it can be more easily looked after with regular care and maintenance. Of course, other factors like the paint used will also contribute to how your chair wears, so maintenance is key.
Maintenance:
If you plan to keep your metal lawn chairs outside all year round, it's vital to look for chairs that have protective features in place. Andre Mellone recommends choosing a chair that is UV and weather resistant at the minimum. Both of these factors will help to stop your chair from fading and looking progressively more worn over time. You should also regularly wipe your chair down with warm water and a cloth to prevent marks from building up. If you live in a place that has a regular rainy season, it's best to store your chairs away, either in a shed or on an enclosed porch.
Color:
Interestingly, it is often the color of a vintage metal lawn chair that lends it a vintage look. Colors like refreshing teal, fire engine red, or sunshine yellow all signal back to the 1950s and 1960s, when bright colors were commonplace in furniture. Chairs modeled after later decades like the 1970s and 1980s are usually in groovy colors like orange contrasted with brown. However, don't let your love of color get carried away. You may love the idea of red chairs, but will they match a more understated porch? Though you should choose your favorite, consider how different colors will work with what you already have.