How exact digital copies are IR codes saved into new learning remote?

Is there any code degradation, if such a learning remote is used as master to program new remote controller?

Should we keep the original remote what ever it costs or is it enough to create button copies in some cheaper remote with learning function?

Or when in a remote site an IR code has to be transferred to a new unit, is it enough to take copy from copied remote and ship it by post?
That means a copy of a copy will be used as remote master for programming.

Of course, most obvious response is just to check it out but what do you think, is this method reliable to be considered as IR code backup option?