Should you also not use any skills you gained at your previous employer at your new employer? Not to mention any techniques you learned about that may help your

Should you also not use any skills you gained at your previous employer at your new employer? Not to mention any techniques you learned about that may help your current employer? Would doing so be "talking about company internals"? So how do you ever get a better job than entry level, if you aren't willing to use the knowledge you gained at prior jobs in new jobs?