A Shopify theme is splitted in pages, the pages are splitted in sections and the sections are splitted in blocks.
Both sections and blocks are reusable inside a theme.
I won’t go into details what sections and blocks are since this is not the scope of this tutorial.
Compared to an open source CMS, Shopify has limitations and one of those limitations is the number of sections and blocks that you can have on a page.
On a theme page sections are limited to 25 and blocks are limited to 50.
Indeed in some cases you’ll need all 50 blocks in one section, this is the case when you build a FAQ page, with answers and questions, or a custom page listing many products or large collections.
If the blocks are not enough for you then looking for an alternative solution to achieve the custom stuff that you need is the best way to go.
Please note that if Shopify supports this number of sections or blocks that does not mean that every page on a theme will support that number.
The number supported depends on the theme developer which will decide how many sections are supported on a theme page and how many blocks are supported in a section.
The number can be increased though via custom coding.