One of the recommendation I got when I started playing was: never sacrifice 3* heroes, keep them until you have a good roster.
After keeping 2 TC13 active for several weeks, I have 7 heroes 4*, which build a decent team, and 71 heroes 3*, most of them are 1.1.
I play all modalities: war, titan, map, etc
I don’t know how many heroes to keep and train for each color. I would say 6, so I can do well in war, but maybe more, because I might want to color-stack.
For instance, green, I have:
Little John 4* 3.60
Carver 3.50 +9 talents
Belith 3.50 +7 talents
Mnesseus 3.50
Brienne 3.50
All the following are 3* untrained: Myggy, 2 x Isshtak, Friar Tuck, 3 x Berden, 3 x Carver, Belith, Brienne
Personally, I love variety, so I always keep at least 1 of each hero. That said, a lot of people don’t bother with Carver at all, he isn’t very good. I would definitely say to get rid of at least 2 Carvers. 1 Ishhtak probably. Berden is really good, but I don’t see 3 being needed. Others might disagree on that point, though. If you wanna compete in monthly challenge events. I don’t think those are worth the effort, but that is a personal opinion. Definitely: 2 Carver, 1 Isshtak.
1 Brienne should be enough. You can eat the 3x Carver. Ishtak is less interesting than Berden so i wouldn’t keep any Ishtak. 1 Berden for sure, #2 or 3 depends on your interest in competing with events
A second Belith could be interesting, depending on your other healer on your roster.
Friar Tuck could shine on some particular, buff booster 3* only raid tournament. Other than that, he is of no real use.
Muggy is a special one and could be useful
Definitely sacrifice most of your duplicates. Although it could be worth it to keep duplicates of some of the 3s with rare skills. Consider - who are your 4s and what skills do they have? for me, I only have Sabina as a dispeller so I kept two Belith and two Mnesseus.
Consider also the rarity of the skills that the 3*s have, such as (also going to give examples for other colors):
Belith - combination healer and dispeller, only 3* who can do that, and only Sabina and Melendor among fours
Brienne - might be worth keeping two for Alliance Wars, as attack buffing is rare and few 4s and 5s buff as much as Brienne does
Kailani / Gunnar - spirit link is rare as well, only Wilbur and Aegir do something similar I think
Hawkmoon if you have few healers
many of the 3* snipers are good (Bane, Berden, Valen, Balthazar, Nashgar, Mnesseus), but if you already have many 4* snipers then you should probably just keep one of each.
I kept only ten 3* heroes, two per color, that I mainly use in tournaments and at the odd occasion for wars. I am trying to build depth in my first six rows for wars. Currently ten 5* and twenty 4* heroes. You must try to select a team that is versatile to fight in various tournaments. I kept in Green Belith and Muggy because I use Belith as debuffer and healer. She ousted Frair Tuck for healing all allies rather than just those close by and she regains mana fairly fast. Muggy I just love and has won several tournament battles against stronger teams with his chameleon trick of revival.
