I am self employed. My country allows me to declare flat expenses on up to 60% of my income. No accounting or proof needed. Real taxation is around 20% on $100K income (including social and health insurance).
So every year I spend about 2 hours with:
- sum all money that arrived to my account in last year
- fill form on IRS website
- update standing orders for health/social contributions for the next year
- one month latter, ring IRS and other offices, just to check all went through
If you move every two months, I would not worry about it too much. Important is:
- you pay taxes somewhere (preferably in your home country)
- you do not work for locals