A big problem!
Some photos are old. some are not even pics of the provider. Some photos are artfully posed, airbrushed and photoshopped to remove tattoos, scars, stretch marks and wrinkles. Misstatement of their actual age by providers is rampant, as is misstatement of weight.
One of the problems are reviews that overstate the providers actual attributes, such as "grade inflation" in the school system.
Most guys out there can find a slightly overweight woman approaching middle age with stretch marks and no muscle tone for free any time they like. Many hobbyists are already married to a woman whose idea of sex is laying there and watching the ceiling fan go around.
There is nothing worse than booking with a woman who has misled you into thinking she is youthful, slender, tight bodied and enthusiastic only to meet your "date" and discovering she is actually what is described in the preceding paragraph.
Good reviews are important, but as stated, are often overinflated for whatever reason. Still, searching for well reviewed ladies with current pics is a good start. And if the price is low, it is likely the quality of the girl is low, too.