Lol myself and my energy. It sounds a little vain, but if you are able to maintain operatorship and know what your limits are, use discernment and learn to know when spirits are pushing just to see if you’ll jump when they tell you, you’re probably fine without anything aside from your will and the ability to say no.
If you struggle to say no in real life however, I would take extra precautions when it comes to spirits. Even the good ones, will fck people over just because they can, if you allow it rather than maintaining who is in charge, who summoned them up etc.
Otherwise I created a servitor to help newbies (or anyone for that matter, I use her also for quick and easy banishment like once a month or so just to reset things around me) that lack that discernment and want to be safe as well. She has the discernment that some of us lack, and won’t allow you to summon anything that isn’t exactly what you intend to summon, she can also shield and ward you against posters and parasites and evil spirits.
I don’t really subscribe to the evil spirits thing however, every entity I’ve come across has as much ability to harm as they do help, and I know angels that will take down enemies for summoners so. I personally think the evil word- is subjective 