Speaking of lightsaber building, is there some sort of rule that you’re only allowed to wield a lightsaber of your own making?

Obi-Wan went on to build his own lightsaber after losing his first one in Naboo despite having Qui-Gon’s. AotC established that the Jedi Order does have spare lightsabers, yet Anakin and Obi-Wan built their own lightasbers after the Battle of Geonosis instead of keeping the ones they were handed. This unspoken rule IMO contradicts Obi-Wan’s line to Luke about his father wanting him to have it when he was old enough.