I have my primary services spread across 3 separate datacenters (AZ's), and backup services across 3 separate AZ's in a region on the opposite side of the count

I have my primary services spread across 3 separate datacenters (AZ's), and backup services across 3 separate AZ's in a region on the opposite side of the country. I pay far less than I would if I put my equipment in only 3 datacenters (2 primary + one secondary) since most of my backup infrastructure is powered off. And I have far more control than I had with colocated equipment, if I find I need to scale up my services by 2X, 5X or 10X, all it takes is a little more money during the time I need the extra hardware (i.e. end of month processing, plus holiday shopping season), I don't need to order hardware a month or two in advance and pay for it all even when I don't need it. What I used to pay for my network infrastructure alone (hardware + support + network engineers) pays for most of my entire AWS compute infrastructure.