I work for an accountant and did not get my taxes to them until the 25th of March. I told them that we don't mind if they extend us. We still have (as of 3pm yesterday) 160 returns to do by Wednesday. There will be quite a few that we will extend. We also have clients that will call us Wednesday afternoon and say "extend me" and then show up on the 14th of October to bring in their stuff expecting it to be finished the next day!!!!
Dh and I had pulled it all out in early February to get the paperwork together but didn't find a number and just put it away and sort of "forgot" about it. I didn't forget, since I deal with tax returns all day every day, but dh didn't want to have to figure out some of our home repairs we did. We shouldn't owe anything.