Dont' use RAR archives for files

I see that some developers send their files using RAR archive. It's convenient to send files in archives. It's ok. But RAR archivator is paid software. File receiver may not be able to extract files. There is a simple solution for this problem. You should use ZIP achive for packed files. There is a lot of free tools which allow unpack files.

Conclusion: ZIP file should be used for files sent to client. You may use other formats if you are 100% sure that receiver will be able to unpack files.