Natural fibers wear out more quickly, it's been a bad few years for cotton harvests, and the way the soaker is sewn it there are points which naturally wear first. I hear 9-12 months for hole development, from many people.
I didn't like the fit. On my 30 lb 2 year old they were bunchy and lumpy. Plus taking forever to wash and dry.
I much preferred Grovia AIOs. Smooth trim fit, faster wash and dry. The extra doubler being snap in meant everything laid flat, and I didn't have to use more absorbency than I needed. I just laid it on top, didn't snap it in, because then it was really easy to get poo off.