Turn off auto cleaning, do nozzle checks yourself. Use the cheapest 8.5x11 paper you can find for these. (Note that you can re-use a sheet by loading it as a single sheet, changing it to think it's a roll by hitting the left arrow, and advancing the paper down somewhat by hitting the down arrow. You can fit 5 nozzle checks per side, 10 total, this way. Down arrow on single sheet mode advances the paper all the way for it to be unloaded.)
Pay or con others to be those people lifting the printer. I had no part in lifting mine.
I learned from my HP 5500PS 60".
When it says a cartridge is down to 1%, there's really a LOT more in there. But as langier mentioned, when the percentage gets low it asks for a new one when cleaning. You have to decide if you throw out a lot of ink or play the swap cartridges game.
Update firmware. Yours might have it already, but there was a bug where some ink cartridges were improperly rejected.
Others will disagree, but I recommend not using the cutter for canvas. It cuts just fine, but at least for me it created a ton of debris in the printer that would fall on the canvas, preventing ink from hitting it in a few spots. Otherwise, vacuum the inside out often.
They aren't that expensive, but you can find maintenance tank refill sponges a lot cheaper. It's just a sponge - I don't mind using third party here.
Most (all, in my experience actually) ink goes into the right maintenance tank. If one completely fills, it won't print anymore. When your right tank gets to 10%, switch them. I, then, have left that initial one at 10% on the left, and it never fills up more. I believe (but don't know) that the only time the left one is used is when borderless printing is used, which I don't do.
Some day the head carriage will bounce from side to side, possibly for quite a while - up to 15-30min? It's auto adjusting something, and it isn't kind enough to tell you that. It's not broken. It just doesn't want you to meet your deadline.
Don't know if it could hurt something forcing it, but I sometimes have to force the roll to rewind by grabbing the roll end caps and twisting them. Sometimes my media loads with a foot or so advanced, and it thinks it's all the way up, so the rewind button (up arrow) won't go farther.