If you are looking for probate records from Monroe County from the 1800s then there is a service online called Sampubco that will make a copy of a will (1821 – 1901) and send it to you. They get the will from microfilms that were done by the LDS many years ago. Sampubco has created an index to the wills that can be viewed online so you know if there is a will available.
Not all estates had a will, In fact, probably more estates do not have a will. The legal term for an estate without a will is intestate. Sometime around 1930 the local chapter of the Daughters of the American Revolution (DAR) extracted records from intestate estates from 1821 to 1874. There were two volumes, the first covered intestate estates from 1821 to 1863 and the second covered estates from 1863 – 1874. Those two volumes have only been available in Washington, Albany and in the Rochester Public Library; until now. The Rochester Public Library has now put the two volumes online. Both volumes list the name of the decedent alphabetically. Then it lists residence and a date of death. After that is a list of heirs that usually includes their residence. There are people in these estate records that are not recorded in any other place. These are the links to the records:
Another similar volume is simply called Married Daughters. This contains an alphabetical index to married daughters of decedents that are listed in estates. The first part of the volume is a listing from the intestate estates and the second half is married daughters from those estates with wills. This can be especially helpful when looking for maiden names of women.
All three of the volumes described above are PDF files that have had optical character recognition (OCR) run on them. That means that they can be searched for names or other words. The original documents were carbon copies and often the typing was far from clear. So it possible that searching any of the documents might not come up with a name even though it is the document.