robstarski:
I'm told the game becomes so much harder when you move up tiers....maybe I want to stay at Pro?
The two hard steps to come are Master and Legend, causing a step back in the tees. Both are best absolved with new equipment - credits to spend in the Pro Shop for clubs and subsequently for custom balls - a steady cash flow because they wear and get lost. OTOH, the real fun comes with this custom equipment - an investment into recreation.
robstarski:
What causes users to move up Tiers? Number of rounds played? Score average?
Both, together. With an average of 67 and 20 rounds as a Pro you will be promoted to Tour Pro (only faster greens).