It is scientifically impossible to build a ferruled rod to the exact same characteristics as a continuous rod section. It will be heavier, stiffer, and possibly weaker because of stress concentrations. It's like it is not possible to have a knotted joint in the line behave as though there were no joint.

So, the only reason you would want joints in your rod is for portability. And the less joints, the better. Only you can decide that degree of portability you want. All the way from getting it into your car crosswise to sticking it in a suitcase.

There is work afoot by Magnus Argus and Grunde Lovell to characterize rods by their Polar Moment of Inertia (MOI) as well as their static strength (exhibited by ERN in the CCS method). I would guess that the more sections you have - the higher the MOI (bad). So all that money you spent on that ultra high modulus graphite is going to be somewhat wasted. More will come out on this later.

So what does all this mean? It means multi-piece rods are a compromise for portability and you should not compromise beyond what you need.

All that being said, the joints in rods today are hardly noticable. So the compromise is probably minor. The only way you can be sure just what that compromise actually is, would be to cast identical rods (identical except for the #of ferrules that is) side by side. I have never done that and I don't know anyone who has (key word - identical).

And as JC said, there are many multipiece rods available and because of the skill of the designers, they are okay.

But an acceptable compromise, none-the-less. And science will say that there is a difference.

As for me, I have never found it.

Godspeed,

Bob