What I have heard about AL wiring is that the wire itself is not the problem. The problem arises from the fact that the wiring and the switches/outlets are dissimlar metals.
Over time, this junction between dissimilar metals corrodes (because that’s what happens ‘tween AL and CU when they are exposed to air and in direct contact with each other for a long time). This corrosion can result in a gap between the metals, and gaps between the metal means arcing and arcing means fires.
Anyway, to fix it you have to go through all the switches, outlets and breakers and put some special goop on the junction and use special connectors to prevent any corrosion.
What you don’t have to do is change all the AL wiring. So, the cost to fix any issues is usually less than most people think, though not trivial.
