It took me longer than 3 months to really get good with my DE. I also don't get good shaves with Derby blades.
I always got really close shaves with Mach III... too close. I'd always end up breaking out and getting ingrown hairs, which made daily shaving difficult/painful. Even if I do too many passes with a DE, I never get ingrowns.
i used to think this for maybe the first 6 months of using a de but keep working on your technique and you will be able to get better shaves than with carts
That's it. Are Derby's the only blades you've tried? Is the Merkur the only DE that you've tried? What are you doing for prep? Details matter and will help those attempting to give you feedback. Be careful making broad, sweeping generalizations so early in the game.i dont know if its because its only 3 months that i shave with safety razor