I fly a lot less than most here on the forum, only about 4-5 times a year. As my main destination is Stuttgart (family there) I have the grand choice of BA or Eurowings. Major deciding factor is the price.
For Christmas this year BA wanted over £300 more than Eurowings, so an easy decision.
For my trip next month pricing was similar, but BA has an earlier outbound and a later return flight, giving me four extra hours with my family, which I'll happily take.