If you are allergic to shipyard repairs derelict is the way to go, take a look at maintenance/recovery costs of heavily d-modded ships.
Add field repairs and losses do not really matter, combat will be profitable.
I know Derelict Ops reduce combat and campaign costs. Does not matter because I do not want clunkers in my fleet if I can help it. It probably would need to be overpowered like the older tank version of the skill for me to think about overlooking ugly d-mods.
I get Hull Restoration because it too avoids shipyard repairs to an extent (prevents d-mods sometimes and removes few at a time). It also has the side bonus of boosting max CR, so it is a consolation prize if I cannot get Leadership. I consider Crew Training mandatory for some ships (especially Ziggurat and Radiant with Beta+ core), and if I cannot get it because I get too many other skills, at least Hull Restoration can double as Crew Training of sorts.
In previous releases, I did not mind scuttling ships and rebuilding them at Orbital Works, but that is not really an option once s-mods or exotic/limited ships get involved.
I get Field Repairs on the way to Ordnance Expert (more flux is good) and Polarized Armor (faster venting feels great for flagship). Would like to get Bulk Transport at times to speed up civilians on the map, but I never take it now.