The best age to castrate goats?

I have seen a few gals on the internet claiming to be experts on goats stating that it is better to castrate goats when they are older than 5 months. I know with cattle it is easiest on them to castrate them when they are under 4 months old. Aren't goats balls well developed by the time they are 6 months old and since they are usually done without painkillers that seems mean to wait that long. Any other gals raising goats that can offer advice as to why the so called experts say wait longer