Use them for Faction Guardians. :)

Agreed. 

I only have a couple of dupe legos but I use them as Faction Guardians since they apply the bonuses to all of the Legos in that faction. 

Might also be because my dupes are:

1. Acrizia (for CB a second Acrizia does way more for me than empowering her).

2. Lugan (never leveled either of them past 50 and that was just for CvC points).

3. I did use a Cillian the Lucky to empower my Ronda.

Facton Guardian first, and empower after 

I think it depends- i empowered trunda, ukko and brogni as i use them quite a bit, but i used dupe mountain kings as faction guardians as i dont need a stronger MK.... 

I would say there are very few situations where it's worth empowering, unless you can reach +4.

+2, +4 or bust

even then I'm often going to be hesitant due to the value FG brings 

Anyone worth empowering, you likely get more value of building a 2nd... and even a 3rd for the top notch tag champs 

I have no faction filled with guardian yet, doubt I'll start empowering even when I do

often gonna be true, can think of quite a few cases of Hydra champs and Tag champs I wouldn't feed 

though I'm still not using my 2nd rotos but this may be a user error 😂

If not using at all, then yes user error lolz

is built, booked, and masteried and used sporadically but if I somehow get a 3rd Rotos I'm going to have a fun decision on my hands 🤔

Kit us too unique for me to "discard" one.  Obv tag, but who knows what new pve content only a specific rotos build would be the solution 

I use one on my udk team, and the other on my cardinal team. But I'll admit that second one is seeing very little use.