Make sure you have the right height. Put your chair against the dining table and sit to see if the heights of the chair and the table match each other. Your legs shouldn’t be touching the underneath of the table and the chair should smoothly go under the table after use.
Where are you using them? Are you dining outdoors or indoors? Most wood furniture should be kept indoors except teak while iron and plastic chairs can be used outdoors extensively with no problems. However, keep in mind that the color of almost all materials fade away in direct sunlight over time.
Are you going to move them around? We all move around dining chairs to a degree when we need extra seating on some special occasion. The lighter the better when it comes to moving. However, do not sacrifice durability for weight. At the end of the day, a chair is there to support your weight.
Stack them or fold them. Being able to stack or fold the chairs when mopping the floor or moving to a different place is a great thing. If that’s what you want, trying stacking or folding when you’re looking at the store. Again, make sure it’s still strong and sturdy enough for you.
Think about how you will clean it. Sooner or later, with use, chairs get dirty and dusty. How will you clean it? Chairs with simple design and construction are a lot easier to clean than chairs with complex artwork or details.
Plain or with upholstery? As long as the chair is comfortable for you, both are fine. Having upholstery doesn’t necessarily mean that a chair is more comfortable. Also, poor quality upholstery is sometimes easy to rip and hard to clean up. It can also make your seat hot in the summer.