To the contrary, the series suggested that the ship would select any seemingly arbitrary warp factor for going from A to B. Fandom derived the concept of warp 6 cruising, which is sort of logical in terms of current naval parlance when warp 7 apparently was used in emergencies and anything beyond warp 8 was avoided.
The TNG Tech Manual got fairly clever mileage out of this by claiming that all integer warp factors are cruising speeds, while all non-integer ones are undesirable. From this, we could quite naturally develop the concept of "top cruising speed", that is, the idea that a starship has several cruising speeds, most of which fall on integer warp factors. The twist here is that the cruising speeds above warp 9 are no longer integers. But it might well be that W9.975 is a cruising speed while W9.96 is not...
Timo Saloniemi
The TNG Tech Manual got fairly clever mileage out of this by claiming that all integer warp factors are cruising speeds, while all non-integer ones are undesirable. From this, we could quite naturally develop the concept of "top cruising speed", that is, the idea that a starship has several cruising speeds, most of which fall on integer warp factors. The twist here is that the cruising speeds above warp 9 are no longer integers. But it might well be that W9.975 is a cruising speed while W9.96 is not...
Timo Saloniemi