(a2a) Summoning demons to show up whenever they want is an incredibly bad idea.
Instead, a real magician aspires to summon demons whenever the magician wants.
Really it’s just a case of Setting Boundaries in a relationship. If you’re the boss of a company, you want your employees to turn up when they’re supposed to, and do they job that they’re paid to do. You don’t want them to be bad timekeepers, or make unreasonable demands of your time or your good nature, or stalk you at your home.
Same with demons: you are meant to be their boss and they are your employees. A lot of people with superiority complexes feel bad about commanding demons, but if a Manager can give an instruction to his / her team-member and still be respectful to them, it’s really not that different.
Source: Alex Sumner’s answer to What spell do I use to summon demons that show up whenever they want? – Quora