There have been a number of different threads dealing with this issue.
My personal view is that:
1) maps are created for a purpose, and every map needs to fulfill that purpose.
2) Maps are designed to communicate information, and communication of that information must be a priority.
3) Maps are iconographic in nature.
Which means that I tend to redraw maps at different scales (covering different areas) with different detail and different items of focus. While I may try to keep these different maps geographically consistent, I'm not overly concerned with locking them all together like jigsaw pieces, as any differences can be blamed on different projections, views, "measurement" errors, or general artistic license to ensure clarity of communication.
A common example will be of the depiction of rivers on an overland (large area) map. The width of the lines of the liver, and even the route of the river are all approximations, and if scaled up to a local map would make little sense...