hairline cracks

Hi, new to this forum but have recently had the whole back of our Victorian terrace rendered. Old render was hacked off back to brick and then 2 coats of sand and cement render applied. It has been complete about a month and we have just brushed off the loose sand in order to paint and found two...

IF not allowed, please ignore this post as I am not a plasterer. Just a new home owner... trying to learn. We have recently bought a 1967 house nad had all the original wallpaper taken down. There is "crazed" hairline cracking almost throughout the house. The walls are hard plaster. Some walls...