Service programs are implicitly bound by reference into the programs which use them. The other type of binding is by copy, where an actual copy of the module is bound into the final compiled program object. Thus, if the module changes the program must either be updated (via UPDPGM) or recreated.
So, if the service program is changed (via UPDSRVPGM) or recreated, the programs which use it will automatically use the newer version.
There would be additional considerations If the signature of the service program has changed. If so, that is where using binder language is beneficial, as it provides support for previous signatures of the service program.