Dito Naomi...   Experience & good turnaround should be paid for properly.   If someone finds that they cannot do a job in good time then give it to a good abstractor/researcher who can do it fast.  Most of the time the customer will be grateful for a job well done & will pay in return.  

We are "researchers" so it goes w/out saying that we should research for who we are working. This will save time & money.  Of course, payment up front is never a bad thing for which to ask.