How many MySQL queries per visit I should normally have?

This is highly contextual. For blank WP site out of the box that would be a lot. For heavy site with multiple plugins (which you do seem to run quite a few of) this might be what it takes.

In general the SQL query is retrieval of data from database. Deciding between “many” or “not many” is more precisely answering questions of:

  • is data that is not needed being retrieved?
  • can data needed be retrieved in more efficient ways (in bulk with less queries)?
  • can part of data be made less needed (with caching for example) and does anything prevent that from being implemented or working as intended if it’s already is?