I keep a daily spending diary to keep track of where my money goes, be it in bitcoin or Fiat.Keeping a daily spending diary is an easy way to take control over your spending and to identify some less than desirable spending habits.
Also as an added bonus, by keeping a daily spending diary, you're already halfway there in creating your own personal budget.
Tax-wise, it's your income, not your spending what's relevant. You have to be able to prove where did you get your money from, not where you spent it.
OP: good thread and good advice. Although I doubt that, at this point, HMRC accept private keys/blockchain records as evidence, not to mention reports/screenshots from defunct exchanges, casinos etc. Still, it's better to have something than nothing.
And if you want to be 100% legit and law abiding citizen, you should declare your signature campaign earnings. In the UK, these would have to be declared as other income (you'd need to file annual tax return) rather than be treated as capital gains (even if you don't convert to fiat).
