Any changes to taxes on your 401(k) savings won't change two key tenets of planning for retirement: Save early and save as much as possible.

Right now, workers who have access to 401(k) plans will be able to invest up to $18,500 next year, while participants age 50 and over will be able to put away $6,000 more. Under current rules, investors will not pay taxes on those contributions until a later date.

That could all change if some lawmakers have their way. Limits for pretax contributions to 401(k) plans could be lowered to $2,400 as Congress looks to make up for other tax cuts.

Financial advisers who work with individual investors said they are concerned about how such changes to 401(k)s could negatively impact people.

"They would stop saving for retirement," said David Edwards, president and wealth advisor at Heron Wealth, a financial planning firm in New York.

Behavior plays a part

The reason has to do with behavioral finance, he said. When saving for retirement with pretax money, it feels like someone else is paying for it. Take away that benefit, and saving becomes less appealing.

"You'll get a huge tax benefit when you retire, but it won't feel the same way," Edwards said.

The fact that only certain individuals have access to these retirement plans is unfair, Edwards said. A more beneficial change for legislators to consider would be opening up the Thrift Savings Plan, available to federal workers, for everyone, he said.

Read the entire commentary at CNBC.