Oxygen Concentrator

I care for an elderely family member who uses a home oxgen concentrator 24/7 on a setting of 6. She gets a Drive DeVilbiss 1025 from the oxygen supply company. These machines always die in 4 - 6 months of use. (The first one she had was brand new, the second one prob had about a year's worth of hours on it when she got it.) Cleaning the filter did not fix. Is there a problem with this model dying this frequently? Any experience with these?