Are the ERD measurements quoted by manufacturers reliably accurate enough to order spokes or is it a ball park figure and you need to measure each rim just to be sure?
TIA

I usually measure them just to be sure, if I have the rim to hand.

If I’m ordering the rim and spokes at the same time I use the manufacturers ERD, and have had no problems (yet).

Some have strange ways of quoting ERD, Mavic for example.

If you compare the given figure with a couple of independent wheel building sites and all are the same it’s fine.

Best to compare different calculators anyway to double check before ordering spokes.

Anyone else taken a punt without measuring?

Just measure them. Sometimes the sizes quoted can be way out.