Treat text strings with caution. Try and avoid multiple joins and split common joins to separate line items.
Make use of IF ISBLANK() when joining text, if the strings are empty set to BLANK.
Related to Rule:
2.02-05 Create "joins" in smallest hierarchy
2.03-02 Try not to use TEXT as a format, or limit it as much as possible
Best Practices articles:
Formula Optimisation in Anaplan
Questions on this topic? See 2.02-04 Text Strings in our Planual forum.