Axes, arrows and Mana pots probably yes, a good bench definitely, but not necessarily World Energy Flasks.
I played every level only once and I’m ranked 1100th currently.
@ main topic
Quests are for all players. Everyone is allowed to try.
Rare difficulty can be finished after a few weeks of active playing. A rather good rainbow 3* team + a few extra heroes (fully leveled 2* or partially leveled 3*) is enough to breeze through levels 1-9. A sensible use of items pulls you through stage 10.
Epic difficulty is usually beatable after 2-4 months of FTP playing (payers get 4* earlier and can choose which ones to level up, so they will be able to finish earlier).
A sensible mix of 4* heroes at 3/60 or better and the right 3* heroes (Gunnar/Kailani are fantastic if you don’t already have Wilbur) are necessary, as well as the right items for the last few stages.
Legendary difficulty can be beaten after about 4-8 months of active FTP playing. You don’t need any 5* heroes to complete that difficulty, but a rather good choice of 4* heroes and at least a few fully leveled. I did my first legendary event after about 4 months of playing with Grimm and Boldtusk at 4/70,Kiril at 3/60, Skittleskull at 3/?? (had no 5* heroes nor any other 4*) and most of the regular 3* heroes (there was no Atlantis at that time). Gunnar and Kailani saved me several times, the few time stops, dragon attacks and whirlwinds I had saved pulled me through the last stage which took ages to complete. Can’t remember whether it was Pirates or Guardians of Teltoc.
To sum it up, the monthly events are for everyone. However, you need to build up the right teams to be able to complete the three tiers. But it is Not endgame content for high level players only nor is it necessary to pay anything in order to finish. I even think that there should be another fourth difficulty tier beyond legendary which is directed at very advanced players and which requires a very strong hero roster so that also those 10k+ players with a rainbow 5* team at 4/80 and many fully leveled 4* heroes have a hard nut to crack.