Yes, the bugbear of Microhistory raises its ugly head again, with the question: What does “Containing by Estimation Seven Days' Work” mean in 1810 Land Auction advertisement?
To me the genealogical relevance is obvious -- if you are looking for land transactions involving someone in your family in historical property records, you need to be able to identify the record you found actually belongs to the property you are looking for, versus some other property with a similar name. The basic task of genealogy is to establish identity -- the only difference here is that the identity in question is not a direct question about the individual in the source, but the property involved in the property transaction. But in order for someone to know that this is part of someone's estate, they might need to establish that this is the same property as in some other record.
Perhaps this is not a question for Genealogy.SE, but it's not a question for History.SE, either. They don't want questions which can be easily looked up on Google on in Wikipedia any more than we do, so we aren't going to win ourselves any goodwill by dumping all our microhistory questions on them.
If we can't ask questions about how to evaluate source material, then what is this site for?
What information needs to be included in a question to demonstrate its genealogical interest?
It's not fair to ask new users that they have to include more information without giving them some guidance about what that other information should be. Perhaps we should determine what information needs to be included and add this as a new question in our FAQ.
Below the line I am including the information I've found so far, so if our new user comes over to Meta, he or she can at least get a possible answer to the question.
The Free Dictionary defines a close as "A parcel of land that is surrounded by a boundary of some kind, such as a hedge or a fence."
From the context it appears that the estimation of "seven days work" is a measure of how large the land parcels are.
A search for the phrase "seven days work" turned up similar descriptions in The Bradford Antiquary: The Journal of the Bradford Historical and Antiquarian Society, Volume 1 (1900), published in Yorkshire -- on page 60, a description of mortgages says:
With the Hall were sold several closes of land among them being "The Ffalderinge" (containing eight days' work).
and following on the same page are descriptions of several other land parcels.
In Transactions of the Illinois State Horticultural Society, Volume 3 (1904) on page 493 there is a discussion of how much yield can be gotten out of a parcel of land, which says in part:
Last year we had 13 acres of yellow Dent corn, which produced 1,260 bushels crib measure at two and one-half square feet to the bushel. This corn cost seven days' work for breaking the land and two days pulverizing and dressing the ground, one day planting, nine days cultivating, twenty-five days gathering the crop ....
I suspect that the 'seven days work' might be a rough estimate of how long it takes to break the ground, and is intended as a measure of how large the enclosure might be.
Resources for using land records in genealogy include: