Homeowners are expected to spend a near record $317 billion on home improvement this year. The trend is expected to continue, as areas have fewer homes for sale and homeowners have little incentive to move from homes with record low fixed mortgage rates, experts say.

What’s the biggest home improvement mistake that most folks make? Over-improving one’s home can be the costliest, housing experts say. Remodeling magazine found that only attic insulation netted an immediate return on investment (108%). A new entry door was next best (91%). Even the popular minor kitchen remodel only netted an 80% return.

In time, these improvements will net a return. But sometimes homeowners customize and overspend, thinking they’ll sell at a profit in the future, but are unlikely to ever recoup their investments.