Editorial & sourcing policy

We cite primary sources

Every residency rule is researched directly from primary law: IRS publications and the Internal Revenue Code, individual state revenue-department guidance and statutes, HMRC's Statutory Residence Test guidance, and the relevant double-tax treaties. Where a point is contested, we cite the governing case (for example, Matter of Gaiedfor New York's permanent-place-of-abode standard) rather than paraphrasing it. Key guides carry a numbered “Sources & further reading” list so you can verify each claim at its origin.

We name our author

Guides are written by a named author with a public profile, not an anonymous byline. See who writes Tax Days. We do not invent professional credentials. Tax Days is built by people who research these rules for a living, but we are not your CPA, enrolled agent, or attorney, and we say so plainly.

We show when content was updated

Tax law changes. Each guide displays its last-updated date, and substantive changes are logged in a visible “What changed” history. We review the highest-traffic guides at least annually and after any material change in the underlying law (new thresholds, new regimes, repealed rules). Our methodology page explains how rule data is sourced and maintained across 254 jurisdictions.

This is information, not advice

Everything here is general information to help you understand the rules and keep a defensible record. It is not tax or legal advice, and it does not create a professional relationship. Residency outcomes turn on your specific facts, confirm any real decision with a qualified tax professional in the relevant jurisdiction.

Found an error?

We want every page to be correct. If you spot an outdated threshold, a broken source link, or anything wrong, email support@parra.io with the page URL and the correction. We read every report and update sourced content quickly.