Not really. It's more about the purpose of the site/app. If your site is mostly content based, then you likely don't need an SPA. That's the ideal use case for

Not really. It's more about the purpose of the site/app. If your site is mostly content based, then you likely don't need an SPA. That's the ideal use case for a traditional website done with whatever you use (in this case Django/Rails). A wiki, a blog/news site, a business info site, etc... all those are 100% use cases for traditional sites. You also need to ask how often a user will interact with the app and what they'll do. A forum probably doesn't need to be a SPA, since people won't (for the most part) be auto refreshing the page non stop for hours, they'll be coming back periodically to check for new content. On the other hand, if your site needs regular updates, users are going to be using it for hours on end, it replicates a desktop program, etc... then that's a good SPA use case. Team size is more an issue of management and splitting things into components.