My first helper worked almost 5 years. She gave me references. I never called to call to verify. She was a decent helper. She wanted to move out and live on her own and we did not want that so it ended amicably.
My second helper still working (almost 6 years). She gave me references. I spoke to one of them and it was a good reference. She is one of the best helpers we've ever had.
I had a third helper (as an additional helper to my second helper). She marketed herself with certificates, references. I never called to verify. I had to let her go after 3 months. Enough said.
References are important.
You can fake references and certificate but you cannot fake a good reference from an old employer.