I agree with Jim, especially when it comes to turnouts.  I find that adjustments need to be made after the initial build of a turnout as different pieces of rolling stock pass through it (e.g., Sunset Models brass locos that usually have a narrow gauge than the NMRA standard).  Also, I occasionally decide to rearrange track that is already laid.  If the rail is spiked and not glued, it's a lot easier, and I get to keep a lot more of both the rail and the CVT tie strips and switch blocks for reuse.

Todd Sullivan