Remember this: Fear destroys power.
Fear will paralyze you. It’s common to hear things like “bad spirits” are out to get you, and will let themselves in given the tiniest chance.
When it comes to protection spells, if your intentions are fine (e.g. you are coming from a place of positive thoughts and kindness or love) then there’s absolutely nothing to fear.
Don’t let those who are operating from a place of fear control your Magic. You can’t really be succesful if you’re dealing with that mindset.
Another thing to know: Most of the time, a ritual can’t “backfire”. It either works or it doesn’t. But the best protection spell is to keep learning. The more you learn, the less you fear.
Protection spells are there for those who might be dealing with baneful magic or don’t have enough confidence, so they feel a specific need for an extra layer of protection.
You don’t have to cast a circle every time you cast a spell. The circle will give you confidence and a place to practice without distractions, but it’s not always necessary. Think of it as a “safe space”, your training wheels. Eventually you don’t really need it and it’s also good to experiment without it.