How would you abbreviate a state, province or territory in your writing?

For anyone who writes letters or articles etc., how would you abbreviate i.e. shorten the full name form of e.g. a U.S., Canadian or Australian state or territory?

I often see news articles with states or territories shown in two different abbreviated forms: GPO standard and USPS standard.

For example:

Kansas is either abbreviated as Kan. (GPO standard) or KS (USPS standard)

North Dakota is either abbreviated as N.D. (GPO standard) or ND (USPS standard)

If you were writing a letter or article etc., how would you abbreviate a U.S. state? Why?

A similar thing in Australia:

Queensland is either abbreviated as Qld. (old Australia Post standard) or QLD (current Australia Post standard)

Western Australia is either abbreviated as W.A. (old Australia Post standard) or WA (current Australia Post standard)

If you were writing a letter or article etc., how would you abbreviate an Australian state or territory? Why?

U.S. state abbreviations list

State abbreviations

State, Province & Territory Abbreviations - Australia, Canada, U.S.

For me, I generally dislike abbreviations so I tend to avoid them in my own writings. When I do abbreviate a state, for example, though I usually go with the USPS standard simply because I've seen it more often so it seems more widely used to me.