People have answered this question beautifully. But this question is not about giving clients RAW files instead of JPEG, but rather RAW in addition to JPEG. (note the big difference!)

Not having the decency of offering RAW files to your client has got more to do with the attitude of the photographer than anything else. It's like "owning work" or "giving up control" for him/her.

What software code is to a programmer, RAW files are to a photographer.

If software developers (companies and corporations alike) can share their entire source code with people, photographers too can share their RAW files. Remember GNU/Linux, Android, VLC Player, Mozille Firefox, Chrome and thousand other amazing products are all open source softwares and have made this world a better place.

I always offer RAW files. But almost always, people don't need them because of reasons very well stated in other answers here (huge size, incompleteness of work, not being able to view with default photo viewers on laptops and tablets etc.). But the important thing is that, I offer. I think every photographer should.

Few things to note here:

• RAW files can be edited. With minimal technical knowledge, one can edit RAW files such that they don't have any record (modification time-stamp etc) of the edits made. So the comparison of RAW files with negatives is moot.
• A client should be made happy with the work the photographer has done. His/her quality of photos should bring that client back and bring additional clients based on that client's feedback to friends/relatives. Getting additional money from client for an extra-sized copy is simply an unfair business practice!

People have answered this question beautifully. But this question is not about giving clients RAW files instead of JPEG, but rather RAW in addition to JPEG. (note the big difference!)

Not having the decency of offering RAW files to your client has got more to do with the attitude of the photographer than anything else. It's like "owning work" or "giving up control" for him/her.

What software code is to a programmer, RAW files are to a photographer.

If software developers (companies and corporations alike) can share their entire source code with people, photographers too can share their RAW files. Remember GNU/Linux, Android, VLC Player, Mozilla Firefox, Chrome and thousand other amazing products are all open source softwares and have made this world a better place.

I always offer RAW files. But almost always, people don't need them because of reasons very well stated in other answers here (huge size, incompleteness of work, not being able to view with default photo viewers on laptops and tablets etc.). But the important thing is that, I offer. I think every photographer should.

Few things to note here:

• RAW files can be edited. With minimal technical knowledge, one can edit RAW files such that they don't have any record (modification time-stamp etc) of the edits made. So the comparison of RAW files with negatives is moot.
• A client should be made happy with the work the photographer has done. His/her quality of photos should bring that client back and bring additional clients based on that client's feedback to friends/relatives. Getting additional money from client for an extra-sized copy is simply an unfair business practice!