Is there a need to set Objects to Nothing
VB uses a so-called "reference counting" garbage collector.
Basically, the moment a variable goes out of scope, the reference counter on the referenced object is decremented. When you assign the object reference to another variable, the reference counter is incremented.
When the counter reaches zero, the object is ready for garbage collection. The object resources will be released as soon as this happens. A function local variable will most likely reference an object whose reference count never goes higher than 1, so object resources will be released when the function ends.
Setting a variable to Nothing is the way to decrease the the reference counter explicitly.
For example, you read in a file, and set the file object variable to Nothing right after the ReadAll() call. The file handle will be released immediately, you can take your time process its contents.
If you don't set to Nothing, the file handle might be open longer than absolutely necessary.
If you are not in a "must unblock valuable resource" kind of situation, simply letting the variables go out of scope is okay.
The very last line of the help topic for "Recordset.Close" in the Microsoft DAO help and the Access Developer Reference is this:
"An alternative to the Close method is to set the value of an object variable to Nothing (Set dbsTemp = Nothing)."
http://msdn.microsoft.com/en-us/library/bb243098.aspx
With that in mind, this article from the Microsoft Knowledge Base entitled "How to prevent database bloat after you use Data Access Objects (DAO)", tells you that you should explicitly close if you don't want your databases to bloat. You'll notice that the article is a little vague about the details; the "Cause" section is unclear, almost to the point of being gibberish.
http://support.microsoft.com/kb/289562
SYMPTOMS: A Microsoft Access database has begun to bloat (or grow rapidly in size) after you implement Data Access Objects (DAO) to open a recordset.
CAUSE: If you do not release a recordset's memory each time that you loop through the recordset code, DAO may recompile, using more memory and increasing the size of the database.
MORE INFORMATION: When you create a Recordset (or a QueryDef) object in code, explicitly close the object when you are finished. Microsoft Access automatically closes Recordset and QueryDef objects under most circumstances. However, if you explicitly close the object in your code, you can avoid occasional instances when the object remains open.
Finally, let me add that I have been working with Access databases for 15 years, and I almost always let my locally declared recordset variables go out of scope without explicitly using the Close method. I have not done any testing on it, but it does not seem to matter.