A church that I attended had a website that has gone menu crazy. Twenty-two menu items on the church home page in two areas. It has a school, too, which has SIXTY menu items. As a web designer, I know that it can get kind of difficult to maintain a website with more than ten menu items.
Yes, you want to provide relevant information to people, but adding a menu item for every single thing you do is like posting a photo of your dinner on Facebook. Imagine showing up at this church website as a parent wanting to send a child to the school, navigating through tons of menus, and then seeing an outdated (forgotten) Staff page that doesn't line up with the teacher pages. Oh, I forgot, each teacher gets a page with as many menu items as they want, which means some have TWENTY more menu items. And the church council has another dozen.
The church and school I mention (which really do exist) are in a bind because they can never fire their website designer at this point, and if that person leaves the church, what then?
When I build a website, the only thing that really matters is getting the menus right. I'm good with images and design, but a client who wants a new menu item for every possible reason will regret it. I tell everyone that 5-10 is a good starting point for a church. Sure, a school can have a teacher page, but a web designer needs to help churches and schools how to figure out how to do things simpler, not more complicated. A web designer who wants to complicate the design is likely on the payroll, and that's the best way to keep the cash flowing in.
It's way more important to have good content that gets searches to your website rather than dozens of menu links. A CMS like Wordpress (the one the aforementioned church uses) is perfect for putting articles in the right place. Joomla (which I use) is slightly better in some ways, but they both work about the same.
You can always ask for more menus later on if something just does not fit. What I'd recommend for teachers is a single article for classes with an embedded Google folder for assignments. When I was teaching, I created my own websites with lots of menus for my classes, but I eventually learned to simplify because the students got confused. If your church or school has too many menu items, you are confusing people. Discuss organization of the website before implementation, and use articles in place of menus where possible.