I second the Calumet shutter tester; easy to use, just takes a minute or two per lens, and also will show you the spread of what your shutter fires at, or the precision, which is important. My experience is that many older shutters, like ILEX tend to be off in terms of accuracy, but if you know how much, you can make a simple adjustment.
I just got a Dagor lens in an ILEX, and did a quick test; the 1/50 speed was actually 1/30, and the 1/25 was actually consistently 1/15 second. Very important to know for portraits. For landscapes I tend to use the B setting, as the slower speeds (1 sec.) of older lenses are usually not precise.