This is like "how often will I need to open up the bonnete (engine) of my car once I start driving?"
I do not know which admin password you're talking about and what kind of an account have you bought. For maintaining a
website hosting content idealy FTP username and password is used quite frequently and for database management you need access using the Cpanel password. To create domains and hosting, you often would need the admin password to WHM as ofen as you get a new order.
That's all I can think.
Regds
IJ