I haven't once been told to have tainted coins, even though I mix regularly.
Same. As soon as any merchant tells me my mixed/coinjoin/swapped/otherwise obfuscated bitcoin isn't good enough for them, I'll be immediately leaving that merchant for a less stupid competitor.
What exactly do you mean round amounts? You mean don't send 0.0005 btc and send like 0.000523?
Yes, exactly.
Let's say you have one output of 0.00052376 BTC. You make a transaction which creates two outputs, one of 0.0001 BTC and one of 0.00042076 BTC, with 300 sats paid as a fee. Which of the following scenarios is more likely?
- Someone requested payment of 0.0001 BTC, and whatever is left over is the change.
- Someone requested payment of 0.00042076 BTC, which just so happens to be the amount to exactly match your output and leave you exactly 0.0001 BTC as change.
Obviously the first scenario is far more likely, making it trivial to identify which output is payment and which is change. If instead, your two outputs contained 0.00010814 BTC and 0.00041262 BTC for example, then it becomes far more difficult to figure out which is which.