Well, it all depends. The block has not been machined before? Building a race engine or blue-printing a never prepped before engine? Then you might trim 0.005 off the block to allow you to get the crank's axis line perfect. This is normal race-prep practice. You only need to do it once. Next time, you just shave the caps.
However, normal practice for overhauling an inservice engine is to just trim the caps and that is all I would do with the following caveat.
These engines are getting to the point where they have been overhauled many times. You're no longer trying to correct manufacturing tolerance variations. In the interests of the viability of future rebuilds, it is important to check first and only perform necessary machining. A example of this is the cylinder head on both the TC and Renault engines. Most machine shops routinely cut the head surface true without checking if it is necessary. It doesn't take many cuts, especially if they are carelessly large, and your head is toast. Machine shops also routinely resize rods, bore blocks to the next oversize, etc. All well and good for an engine that is never going to be overhauled again but a problem for our cars.
Just keep in mind, check first and only do what is required. Future owners will thank you.
