The cost to change is high, but nowhere near the cost to upgrade. I wasted so much silver upgrading crap gear in the beginning and average gear even up until now.

Three most important things to learn fast, imho:

1) How to farm food efficiently. 

2) 6 star one hero that can do #1 first and foremost. Don't worry about challenges (do daily and weekly of course) and missions, they aren't going anywhere. 

3) Equipment understanding and management.  Don't over invest in shit. In the beginning focus on the primary stats of each artifact and how the align with your champ. Later on, substats are crucial and you may upgrade something to 8 and get 2 bad rolls. Stop and move on to the next piece.

I think there are 3 levels of this next phase. I'm at the beginner. I basically have all my primary in 5* 16+ gear with good primary stats with good set bonuses. This gets me to where I can do golem and dragon up to 17/18. 

I'm moving into the intermediate phase, where I can incorporate 1 new piece that gives me really good improvement or a 2/3 piece swap that jumps me significantly. I figure 1 to 2 million to get a new piece to 16?

I also wait to make big changes for artifact enhancement event. Amy opportunity to get books must be seized. Would suck to run out of silver because I upgraded and then event popped up. I've done this. Or to have silver but waste it upgrading something you can't use right away. I've done this too.

All that said, I'll take a free equip swap day!

I would also suggest for this, 1 day a month to remove artifacts with no costs. To see if you can run different sets on champs. If you do it now you lose like 600K for 1 champ... (up to 900K with acc)