Enrichment studies

Hello, I’m wondering how many enrichment volumes people have brought?

I have a 6 year old and younger children I plan to homeschool as well in the future.

And I’m wondering how costly it will be to use the simply charlotte Mason enrichment program for future years.

We are in New Zealand so it is a essentially double the cost. I’m wanting to have a good idea of what it will look like for us before I invest.

From my understanding you use any volume (we would start at volume 1) and use it for one year. However then you can cycle back and use it again in future years? How often do you cycle back to the same volume? For four years in a row are you buying a new volume, and extra books? With the exception of the books you have already bought that carry over to the next volumes. And then reusing these volumes every four years?

So after the first four years you’re sorted for the rest of homeschooling years, if you choose to use these volumes in high-school? How common is that for people to use right through?

Apologies for multiple questions at once..any info on how these volumes work practically and how much money you’ve invested would be really helpful. Thanks in advance.