Hi:
The RTF specification has fairly strict requirements for what RTF control strings go at the top and bottom of an RTF document. Using 1 ODS RTF "sandwich" around all your report procedures is the only way to get ODS to put all your report output into 1 RTF file.
http://support.sas.com/kb/24/034.html
http://support.sas.com/kb/35/375.html (also applies to ODS PDF)
If you create one RTF file with ODS on Monday and then a second RTF file with ODS on Tuesday, you cannot use ODS to bring those 2 files together into 1 RTF file. You would need to combine the 2 files using a word processor (such as Microsoft Word) or you could "post-process" the 2 RTF files with a program to remove the control strings at the top of one file and the bottom of the other file to bring them together....and even then, you have to be really, really sure that you understand how the RTF control strings work so that you don't accidentally corrupt the RTF file.
So, by far, the easiest method is to make 1 ODS RTF sandwich with all your report code.
An alternative approach is to use ODS HTML or ODS MSOFFICE2K (another HTML-based destination, but Microsoft flavor of HTML) -- you CAN append a new file to the bottom of an existing ODS HTML file. Microsoft Word (assuming you have Office 97 or higher) can open the HTML and then you could resave the file as a .DOC or leave the file in HTML form and keep appending to it.
http://support.sas.com/kb/23/660.html
cynthia