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- Split your purchases into ones that you are comfortable on record and uncomfortable on record (having a blank record is anomalous and may get highlighted) - a good tactic is to use cash only for certain goods like alcohol.
- Depends on nation. In North America it seems that cash will be with us for the foreseeable future due to situations where digital payments are not accepted or cannot be accepted (legal marijuana dispensaries, pop-up restaurants or food trucks that don't work with credit cards, person to person sales that no one wants on their taxes, and so on). That doesn't apply to every location, so maybe do some research about the spending habits in your nation, and see if there's ways around tracing (such as using paypal or virtual cards to abstract purchases online).
- In my area (NA), cashless and mobile payments are largely the norm, but they co-exist with other methods because of accessibility - not all communities are banked, and not all people have smartphones with NFC and access to credit. So we kind of have a buyer's market right now.