For simple sites, static is great, but if it becomes more complex (even just lots of pages sort of complex) then some sort of templating, even just through basic PHP includes, becomes very helpful to keep it maintainable. Example: I help look after a site with 3K static HTML pages and it is impossible to make any global changes without literally months of manual work. :(
For my own site I use a static site generator, which is another great option, but that comes with a much steeper learning curve unfortunately.