This one...

 

I finally upgraded my base. Coffers were overflowing... can't spend it fast enough just with attacks so I need to upgrade the radar &/or research lab so I can dump some of this gold... can't upgrade those unless I upgrade the base.

 

Wow lol you haven't uncovered the whole map yet?

 

Overflowing coffers? I live OP Reward to OP Reward...

 

Nope. I upgrade slowly. One item at a time unless I'm forced to level up like this.

 

 

I think I did resources first, then radar and upgrades along with HQ, sprinkle in weapons here and there, and lastly carrier ships and gunboat.

 

Each and every bldg, gun, boat, tank, person - everything. When they're all upgraded to the point where I have to level up. ...unless I get "overgold" that's happened twice.

 

Oh, wow... That is going to take you forever.

I went for the stuff that is actually going to help me. Tank upgrades drove it for the longest time until the Armory upgrade got too expensive. I let a lot slide including some of my defensive weapons. I have flame throwers that are way behind...

 

Wow, no wonder it takes you forever! Higher levels = higher rewards = easier to level up.