I've been sick for ten years now and still learning about my limitations. Because our limits are always changing, it can be hard to keep up with where they are at any given time! It's not impossible, just hard.
-don't underestimate anything. I mean anything. Something as simple as how many times you went from sitting to standing, how long you were on a computer, a shower, a conversation, what "shouldn't" be considered over exertion unfortunately for us can be just too much
-payback (crash whatever you want to call it) can take way longer than a day to hit. I'm slowly learning this! For me it can take up to a week, which is crazy, a lot of things make more sense now that I have realized that!
-energy can be "fake". Ok, this one may not apply to everyone, but for me I will get adrenaline surges. When this happens I feel like I suddenly have a lot of energy, and I will want to do things, but I have learned the hard way it is fake energy. If I use it I crash hard. It's very confusing, and I still struggle with this one, but if I am able to ride it out and keep to my pacing, things are muuuuuch better!
This is all perfectly said! I also get the 'fake energy' and I think many of us do. It's made worse by the fact that you get excited that you finally feel ok enough to do something, so you do that something, and then another something... Learning to recognise an adrenaline surge is important. The other day, I vacuumed the bathroom, toilet and hall. I wanted so much to do more (my dog is moulting like crazy!), and I physically could of at the time, but I stopped because I knew I was in a surge and I would pay for overdoing it later. Think of it like a sportsman using his adrenaline surge to push that little harder and get that little bit faster; adrenaline helps you push through because it blocks out feeling the bad symptoms.
I used the link
@TiredSam shared years ago and I agree, it is a great resource for beginning to understand your limitations and abilities. I never stuck with it too much, as I kept forgetting to write in the logs or I couldn't be bothered, but it still helped to get my head around the issues.
I think to some extent, it's about learning how much something will make us crash, in addition to what our limitations are. Some CFS sufferers are fine with the phone but not in person socialising - I crash BAD when I talk on the phone. Thus if I need to be on the phone, I can prepare myself to reduce the impact, eg. I usually am lying in bed while on the phone, and my family knows that if I say I have to go, I have to go.
I look at our illness as a delicate balance. It's very easy to use up energy and difficult to create/recuperate energy, but we can look for ways to make up for our imbalances. Remember, we are sick people, and what might seem like "nothing" can have a big impact on our delicate system. When you're looking at what you can/can't do and what causes crashes, look at anything and everything. You mentioned about dust - that's a completely viable cause of problems in CFS, as it might have aggravated your immune system and an increase in immune response uses up energy. Overthinking, over-studying or doing too much mental work can be a problem - sounds ridiculous, but when you consider that our brains use energy and blood to function, it makes perfect sense. Sometimes even eating can cause a crash for me - too much blood goes to my GI system, digestion takes up so much energy, then I get super cold and tired and have to sleep. Weirdly, doesn't matter what I eat, I think it just occurs when I'm on the verge of a crash anyway.
Basically, I look at my body as 'doing things that require energy' and 'doing things that create energy' and try to reduce the first and increase the second. It's not just physical effort that causes crashes, that took me a long time to learn and I think it's really helped me identify some problems for me.