Redefining <leader> to previous mappings in vim

In vim :help leader says that changing <leader>开发者_运维问答 after the moment that a mapping is defined does not change the mapping. So how can I update my already mapping that used <leader> with a new value of <leader>??

Herbert gave the right answer: the <leader> shall be defined in the .vimrc. We don't want a completely cumbersome procedure to change <leader> on the fly. It's the same with <plug>-mappings.

You will need to execute the mapping command again. If the mapping comes from a vimscript file, you will need to reload (:source) it.

I guess it is useful because you won't need to edit mappings on vimcscripts that use <leader>