RTC Attribute ID/ Name space formats

As far as I can tell, as long as the ID is unique (in the domain e.g. attributes) you can use any ID. For the tool the ID is just a string.

Having said that, there is a reason for using com.mycompany.custom.attribute like formats, with a different pattern to the one used by the default template. the most important is, being able to search for this pattern in the process configuration source and  easily find things.

Agree with Ralph ... we tend to not use long attribute IDs, but tend to take the name, lower case it, and put _'s in, so Actual Date (the name) has an id of actual_date.  We also ensure by doing this that no two attribute have the same display name (which unfortunately, we had in the past) because that makes it obnoxiously hard in the QueryBuilder which only shows attribute Names, and doesn't limit the list if you have in your query a work item type.  So if I have "Next Release" as the name of different underlying attributes (not reusing the same attribute in different work items), you would get multiple of the same display name.  We even had someone (an old project area) add a "Resolution" custom attribute, which makes it difficult (not impossible) to get the right one when building a query (there is a tiny icon, but most people missed it).