I changed out the burner tubes in the propane grill. The first set of burners I got did not have adjustable air inlets. Ordered some different ones and the difference is surprising.
I had a Kenmore (I think the mfg was Char Broil) for 29 years and only had to change out the burners and the like once. The bottom tray finally rusted and it needed some other t.l.c. but no parts could be found. I got a Pit Boss pellet/gas combo at the end of last season. Smoke side is awesome, Gas side is good with some unevenness (hot & cold spots). The whole thing seems to be well built with heavy gage powder coated or anodized aluminum parts. Will see how it holds up.