Aalto to Eames, Knoll to Wenger—these top notch designers on our minds as The Salon Art + Design show opens today at the Park Ave Armory in New York, NY. Since we’re always playing the mid-century eye-spy game on at our local flea or online, we wanted to pick the brain of an expert for tips on collecting vintage designs. We sought out Hudson, NY dealer, Mark McDonald, who knows these mid-century heavy hitters well. Whether you’re just starting out and have your eye on that Eames lounge chair, or you’re looking to expand your collection, here are McDonald’s tips to ensure you bring home a quality specimen.

1. Keep it original: “Seek out items in excellent original condition,” begins McDonald. “If it is a production piece, try hunting down an example that is closest to the actual design date.” (Ex: The Eames plywood chair was made for about fifteen years—a chair made in the first few years of production is more desirable.)

2. Do your research: For a collector, homework doesn’t stop outside the classroom. “Do your research to gain knowledge about construction, materials and any unique identifying details,” says McDonald. This will help you ID the real deals on the market. “Become an educated consumer so you won’t need to rely solely on the information the seller is offering,” he continues.

3. Age is just a number: “Minor scratches or dings are part of patina, the natural age and wear of a product,” says McDonald, “But, it’s best not to buy something that’s damaged (this also applies to original upholstery),” explains the expert who continued to state that many of the original fabric producers are reissuing designs, meaning you can reupholster if the original is damaged beyond the point of no return.

But what about repairs and restorations? McDonald explained that it’s a case-by-case basis (the material, age, wear) when it comes to repairing and can’t be put under a blanket statement. “Your trusted dealer should be forthcoming with the real state of the piece, and help advise what’s best to retain value,” he says.

4. Trust your gut: It may feel daunting working with a dealer who you don’t personally know, but, “Most dealers, if they have been in business for some years and have an established location, have a reputation they value and strive to maintain. Trust your gut as you get to know dealers in your area of interest,” says McDonald. “They may not have your same decor taste, but can understand what you’re looking for.”

But when it comes to feeling comfortable with what you’re paying, he suggests, “There are many sites that list pieces and prices. Most auction houses, like Wright20, have searches of their past results, although auction prices do not ways tell the whole story. Some sites (such as 1stDibs.com) are a good index for high retail prices, but note that these listings usually are marked up at least 20% to allow for decorator discounts.”

5. You must love it: “Collect what interests you, be it a specific time frame, country of origin, or style. Strive for the highest quality and finest examples you can afford for your personal collection,” says McDonald. We agree with the dealer that it’s best to only buy pieces that you love. After all, you’re living with it and seeing it on a daily basis.