Read this, it's a pretty entertaining writeup: Sean Gallagher: How I Learned to Stop Worrying and Love my Threat Model
Use this page from the good guys at the EFF to help assess what your risks are: https://ssd.eff.org/en/module/assessing-your-risks
What do you want to protect? Who do you want to protect it from? How likely is it that you will need to protect it? How bad are the consequences if you fail? How much trouble are you willing to go through in order to try to prevent those?
- For this exercise, our list of things we are trying to protect will be your email account and your phone's photos.
- For each, write down where it’s kept, who has access to it, and what stops others from accessing it.
- Do this on paper, not electronically.
- Think of three possible threat actors who might want to get a hold of your data or communications. It might be an individual, a government agency, or a corporation.
- As an important note, you are significantly more likely to be "hacked" by someone you know than some random internet stranger. This is even more likely to occur with significant others or parents who you may not normally consider adversaries.
- Think about what each adversary might want to do with your private data
- Think about what the likelihood of each adversary coming for that data
- Think about what happens to you if the adversary gets that data
- Now try to answer the question, how much trouble are you willing to go through in order to prevent loss.
- Think about if you had typed this information rather than written it on paper
- What would it take for a hostile entity to capture what you just wrote down if it was:
- On a piece of paper
- A local word document
- A google doc
Now destroy the paper you just wrote on. Or don't. Decide how much risk you incur by keeping it.
One important note is that you might not have anything worth a targeted attack personally, but you have access to other things that might be interesting to other people. For example, your contact lists can be used to identify other, more important targets. Even more dangerous, someone could use your account to send phishes to your contacts. A @navy.mil address is going to have a significantly higher click rate than some random @gmail. You also have access to your network, so someone could use you to pivot to a network you have access to.