Personaly, I've found that haveing multiple ships built for specific endevors is more conducive. For example: A ship designed to be a small fighter can do multiple things a bit, but not very well. As a ship that is built for a specific purpose. Thus an asp can make a great, explorer, and or a great trader, but not a great explorer/trader. An explorer doesn't have any use for cargo bins which would effect range, nor if one knows how to run, need any weapons. One the other hand, a trader doesn't need AFMU's which takes up slots thus prohibits the use of more cargo bins.
I realize that most player's will or would choose a ship based on it appearence rather than it actual usefullness as designed. But I choose a ship(s) based on their designed purpose, buid and engineer them for specific roles.
I've got three conda's all haveing different load outs, and two Pythons both haveing different load outs. And one fighter with a loadout conducive to only doing pew pew and nothing else. One of my conda's is completly built and loaded out for nothing but extrem long range exploreing of space and objects. Basically it will only ever be utilized if and when there are special events. Though I'm not a member of the fuel rats yet. I've got one conda and one python built and loaded out conducive for either long rang or bubble missions, if and when the call comes in to make a rescue. One conda and one python built for bubble or long range passengers, which can be turned into trucks in a moments notice, cause I've got addintional cargo bins for each in storage. And my FAS (gave up on the Cheiftan) all built and loaded out for nothing but pew pew, with a large fuel scoop in storage, in the event that I want to change systems more than a few jumps away.
I realize one may not be able to afford separate multiple mission specific ships, and have to utilize only one or two to do any and all desired missions. Basically making them combination ships. And that's OK, but using a ship built and loaded out for multiple mission, isn't as conducive to it overall design and thus it more versatile, one isn't going to make the amount of cr's in it as they would one that is.
I got into a Python as soon as I could, and though I generally only hauled passenger's, I did have a complet set of cargo bins in storage as to be able to switch out all the cabins with, if and when I desired. Made a lot of cr's and then boough another Python, and thus no longer needed to store the cargo bins, if was easier and faster just to ship the whole ship, rather than the bins or cabins.