I have been dollar cost averaging for a few years and always transferred the coins out of the marketplace and into my Electrum wallet right after purchase. Always into the same address.

Two or three times, I have sent some amounts from that address to another address.

I keep hearing that you should never spent twice from the same address, so am I at risk now?

Could I simply send the whole stash from that address into another unused one in my Electrum wallet?

Also: If this is such a concern, why does Electrum even allow me to spend twice from the same address. What would I need to do if I have 100BTC in address A and I want to send 1 BTC to a friend's address B?