Depends on the project and your personal preference. Either method shouldn't make a difference in terms of performance but try to think about returning in the future. If you come back in 10 years, which will be easier to remember?

Try to keep things as simple and straight forward as possible but efficient handling of queries is something that'll ust get better with practice. I'm into my 2nd year of access development and try to avoid using queries except for big data collections or where necessary. Really helps clear up the nav pane

Gee, thanks! I too using queries for big data collections.

The real answer is it depends.  
Adding to Dan's reply.
You will find many times that by running 2 queries will often speed up your process.

Example:
Let's say you have 10 years of data comprised of a million records.
The data you are looking for may be covering just the last year.
If you first query the whole data set for just the last year (Q1).  Then in Query 2 use Q1 as that data set - the  
query should run much quicker as far as calculations etc because Access doesn't have to run through all of the records.

So again it depends.  The result would be the same, all of the data vs a subset of the data, but the processing time would be reduced.