“If it’s not broken, don’t fix it” is one long-standing piece of good advice that some Maine lawmakers don’t appear to believe is true.

They are discussing bills that would make significant changes in Maine’s “bottle law.” The 33-year-old statute has made the state’s roads and ditches much cleaner than they were before it passed, and has spurred other recycling efforts that have benefited communities statewide.

The law has evolved over time, and now covers all retail liquid drink containers except dairy products and unprocessed cider. Buyers pay a 15-cent deposit on wine and liquor containers and 5 cents on all others, with the fee refundable at 815 redemption centers across the state.

The centers get a 3.5-cent handling fee from the manufacturers, who are responsible for collecting and recycling the containers. The state says the system collects 90 percent of eligible containers, but the beverage industry says it’s closer to 70 percent.

The system is said to employ about 1,200 people, and the state profits by taking the uncollected deposits, which amount to $1.2 million each year.

One proposed change would reduce the number of trips that beverage manufacturers have to make to recycling centers to pick up bottles, a move to make the system more efficient. Another would exempt bottles holding more than 28 ounces, because those drinks tend to be consumed at home and can be recycled in local programs.

Tweaks such as these could be worthwhile — although bottle bill supporters say that exempting larger containers would raise local recycling costs and reduce the income that redemption centers need to survive.

Some would go further: They say the current program as a whole is inefficient, and should be folded into a more comprehensive statewide recycling measure. Recycling programs now are run at the municipal level, and results vary widely by community.

But there’s a danger in changing something that works now, even if it is more limited than a comprehensive program would be. There’s no guarantee that folding drink containers into a statewide recycling plan would work as well as the present system does at collecting them.

If recycling other items could be improved by a statewide system, fine. But leave the bottle law out of it.