76% completed just now and almost all my DASH balance is available to be to sent anonymously and instantly right now.
Then, once you buy a couple of pizza deliveries and thus deanonymize your change outputs and potentially some of your existing unused inputs, you have to start all over again?
Normally you would get lot of denomination outputs after mixing, so you would just use the required amounts of your 0.1, 1, 10, 100, anonymized DASH, so the change would be no problem.
But in some cases you are right, there could be the case that after the mixing you got for example only 1x10 DASH in your wallet, and want to pay a 4 DASH pizza, so then you would have to mix the 6 DASH change, if you are afraid that your DASH are linked to your identity after the pizza purchase.
BUT for me it was NEVER a problem, i always got enough denominations from 0.1 to 100 to just use complete denomination outputs and not care about a change address.