I've often struggled with the concept of letting go and I think the hardest part of working through that is the "when." I've been doing a lot of thinking about this lately and I'm incorporating my views on time more and more. My personal view of time is that, like money, it's just a unit of measurement created from scarcity mindset and in the grand scheme of things, time and money don't really matter. What we feel can and will generally change over time, but being a firm believer in Law of Attraction leads to the the realization that how and when I choose to let go of people or things is really irrelevant.
If I trust in LoA and I am conscious of my own feelings, then I trust myself to know what the right thing to do is and ultimately there are no wrong choices. I find this interesting because I am a very empathic and compassionate person, but I've also learned to realize that sometimes people just want to take advantage of that. This realization is what leads me to know that when I get the feeling that it's time to let go of someone, that I don't need to worry about what happens next. In fact, letting go of people that we fundamentally clash with is actually very healthy for both individuals in my mind. The more energy we waste combating toxic behavior and thoughts of others is actually energy that could be better spent elsewhere in my opinion, plus it encourages or forces them to handle their own issues without being reliant on our validation.
The problems that I seem to run into when letting go of people that I feel are toxic is that I question myself and why I can't do more or help them. The simple truth that I come to is that it's not my place to help or fix anyone that doesn't want that help and while I can help and guide those that want me to do so, it's just not my place to convince anyone else that they are wrong. Truth is something that can't be shown or taught and it can only be realized. Memorizing something and reciting it doesn't make it truth, but knowing something for ourselves makes it "our truth." It's with that mindset that I find it easy to let go of people that are toxic and draining of my energy, even those that don't want to let go of me. It's interesting how the world works and I can see things coming full circle that I couldn't before. Namaste.