I have a large set of books and loads of macros - they all work OK, but I've
been trying to tweak some of them to make them go a little faster.
I've discovered that sometimes adding the With - End With construct to a
macro can make it go faster (as I expected) but othertimes it makes it go
slower.
What are the rules?

Here is an example of a change that made things slower (part of a
function)...
Original:
Set rng = Workbooks("data.xls").Worksheets("students").Range ("1:1")
lkcol = Application.WorksheetFunction.Match(lookupkey, rng, 0)
rtncol = Application.WorksheetFunction.Match(rtnkey, rng, 0)
With Workbooks("data.xls").Worksheets("students")
Set rng2 = .Range(.Cells(1, lkcol), .Cells(65535, lkcol))
End With
rtnrow = Application.WorksheetFunction.Match(lookupval, rng2, 0)
Sinfo = Workbooks("data.xls").Worksheets("students").Cells (rtnrow, rtncol)

Revised, and markedly slower:
With Workbooks("data.xls").Worksheets("students")
Set rng = .Range("1:1")
lkcol = Application.WorksheetFunction.Match(lookupkey, rng, 0)
rtncol = Application.WorksheetFunction.Match(rtnkey, rng, 0)
Set rng2 = .Range(.Cells(1, lkcol), .Cells(65535, lkcol))
rtnrow = Application.WorksheetFunction.Match(lookupval, rng2, 0)
Sinfo = .Cells(rtnrow, rtncol)
End With
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Adrian D.Bailey, Information and Systems Manager, Dept.Human Sciences
Loughborough University, Loughborough Leics, LE11 3TU, UK.
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