Last week, I changed out a block. I had made one block with quite bright lime green, and thought that was to bright for the quilt, so I made another one. The green block was laying around the house for at least a month when I told my husband why it wasn't in the quilt. He said he really liked it. Then I took the orphan block to club show-and-tell, and they said they liked it also. By that time, I had also fallen in love with the block. The next day, it took me about 5 minutes to rip out a different block and another 10 minutes to put the green one in.
At that time, the quilt was sandwiched and glued, but the glue came apart easily enough on one corner.
I had a quilt on my bed for 2 YEARS before I noticed that one block was tilted the wrong way. It had been in 3 quilt shows before that. I'm not telling anyone if you won't. My granddaughter has it now.