It is pure luck. But I were you, I would not hire someone who is toooo experienced!
My maid is with me (same employer) for about 8 years. HOWEVER, I still would NOT recommend her because of her extremely bad attitude, and she uses computer (Facebook) more than me!!!
Why I not fire her? Because of some family situations I need to have two maids.
I don't want to risk hiring another maid who have problems (mental, pregnant, bad smell, whatever). So, I tolerate her. Simply tolerance.
So, you BETTER SPEAK TO HER PREVIOUS EMPLOYER although the maid is with the same employer for long. Sometimes, it doesn't mean that the maid is good. It is sometimes because the employer does not want to take risk (like me)!