Belt sizing

Just wondering if there’s some kind of rule of thumb or any suggestions anyone here can make on the right belt size for my DIY machine. My concern, (just because I worry about things), is that the 10mm wide GT2/2mm pitch belt I’m using is insufficient for the length of my axes, (1500 x 750ish). I’m using 59Ncm/84oz 2A NEMA 17 steppers which seem to be fine, and I’m not really seeing an issue with my belts at the moment, but I’m running conservative settings on speeds and accelerations because I don’t have a rigid frame yet. Since that’s what I’m working on I want to consider upgrading things I might have undersized previously as I progress through the re-build. When the frame is better and I can up the acceleration I want everything to be ready to go.