@house_cat With zippers, it would probably be easy to remove the current covers and have someone use them as a pattern for new slipcovers made from a durable fabric which should last much longer than four years. Be sure to select a washable material if going to slipcovers again.
I would think the cost would be worth it for a chair you really enjoy. While the chair is "naked," your could have them tighten the springs and add some filling for comfort & support.
ETA: It looks like your sofa might be a FlexSteel. It so, perhaps you could order a fabric from their line in the same color scheme? Try talking with your dealer or local store manager if I'm guessing correctly.
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