I repaired some hairline cracks in the joints in between bricks, and repaired a few cracked bricks. Do I need to have curing fires before I get the oven up to full temperature again?

Also, how to bricks get cracked? Is this from getting the oven too hot? I have no idea when the cracks occurred, since I haven't crawled in my oven since I finished it about 3 years ago. But I did very slow, steady curing fires when I finished it, so I doubt they were formed then.