A good, basic, command transfer rule is:

A$.$ If you can't improve the quality of command, don't transfer it

B$.$ The initial arriving chief officer should transfer command when he$/$she arrives on the scene $-$ every time, even though the incident problems have been eliminated

C$.$ The amount of risk we take is driven by who is in command

D$.$ The initial IC should be allowed to remain in command for as long as possible until he$/$she is utterly overwhelmed and then command must be transferred