Different signatures for different recipients
This solution I had in "The Bat" for Windows.
When you type a recipient in TO: field, the signature changes based upon recipient email.
You can define different signatures and connect them with different recipients and they are applied automatically.
So you can define different signature for your friends, different for business partners and different for your mom :)
And then you don't need to switch them manually so it saves time.
The Bat had it like 10 years ago :)