Generally the second one is quite abstract and is mostly tested in court and generally the less connection you have in Poland the more likely you are not considered as Poland being the center of your life such as: - not having company there - not having family (wife, kids) there - not having most investments there - not visiting regularly - not having any income from there
however still you can e.g. have a bank account or own flat that you rent there and still not considered to be a tax resident, probably you would have to prove that there is other country that is center of your life (e.g. paying taxes there, staying more than 6 months, having wife/kids living there, etc.)
What's gets very unclear what happens if someone doesn't have any "center of their life" anywhere - e.g. someone keep travelling for many years and every 2-3 months switching countries, living on the boat. After all e.g. 'donuts' don't have any center that belongs to them.
Ukrainian tax code has similar provisions about “center of life interest” and “staying more than 183 days”, and a backup clause stating that if your tax residency status cannot be clearly determined with the above approach then you are considered a resident if you are a citizen.
I guess this covers the case where you claim that you don't have to pay taxes in Ukraine just because no other country has considered you a tax resident and you never paid any taxes there, so you can't use that to argue that you're a non-resident as far as Ukraine in concerned.
If you have assets or a wife in Canada they may declare you a resident even after a year.
During all of that, I had to pay income tax in Canada, even though I went >2 years then almost 3 years without setting foot in the country.
In Canada, you didn't have to pay income tax if you were outside the country for more than half the year.
Now as a citizen or resident you have a bank account in Canada, any assets (house, car) or even set foot in the country within any given year you have to pay income taxes there.