If they are not, perhaps they should think about financing their 401k/403b plans at the beginning of their careers as many young people in the work place will most likely have to fund their own retirement.
A person who makes 65k, who is maxing at 20% pre-tax is getting taxed on 52K. If they are paying 28% in payroll taxes, they will net approx. 37k not including health insurance , perhaps before tax commuter benefits, etc. , while having 13k in savings.
This same person who "pays them self first can have a nice nest egg built up in years they are also paying off the loan (approaching 100K after interest compounding and increased amounts after raises). Do it before they miss the money.
I know this is the first piece of advice I gave my D, who started maxing out since she starting working and has a good amount of money saved. She is still saving working in NYC, where she rents an apartment without roommates. She will one day have to plan funding to send her future children to college.