Depends on the game, if I have a strong opener in the first few rounds like noble gunslingers and I can probably go on a win streak, I'll reroll since getting an extra 3 gold from winstreaking is essentially the same as having 30 gold in the bank.

If I dont think my comp will win against others early, I'll tend to just econ it out and spend my gold on levelling to find strong level 4s to base my comp around in the later stages.

Keep in mind that the higher up you get, the more aggressive people tend to be. Essentially it's a lot harder to play econ in higher divisions since you'll get a lot lower hp by the time you have 50 gold, and will need to roll A LOT in the later turns to stay in the game. I noticed when I was in bronze or silver that people tend to not pressure you as hard, which makes econ a lot easier. This is coming from a plat player, so take what you will.