Written by Mandy N
(1/31/2013 11:34 a.m.)
in consequence of the missive, Sharing a lady's maid?, penned by Deborah Markus
The Bennet family, although not wealthy, had a comfortable income.
However, the other JA charecters you mention, Emma, Miss Tilney and Mrs Allan are wealthy. These ladies also have their own household by marriage, or, with Emma and Miss Tilney, keep house and servents for their widowed father.
Below, the link shows a lady and gentleman such as Mr and Mrs Bennet, with children on an income of 2,000 pounds a year could afford to employ 8 men and 8 female household servents at least. although this would not specifically include a lady's maid.
Like you, my impression is the household maid, Sarah, was probably not a lady's maid. However, the housemaid probably had skills such as hairstyling to make her useful as an occasional maid for all the Bennet girls.