Use a **side letter** when the request is **LP-specific** and should not apply to all investors.

Good side-letter use cases:
- regulatory, tax, or compliance needs
- government / nonprofit source-of-funds rules
- enhanced reporting
- modest fee breaks
- advisory board seat
- co-investment rights

Prefer the **main LPA** when the change affects:
- core economics for everyone
- governance across the fund
- investment strategy or restrictions
- any term that should apply uniformly to all LPs

Rule of thumb:
- **Core fund terms** in the LPA
- **Narrow exceptions** in side letters

Keep side letters rare, specific, disclosed where required, and tracked carefully to avoid operational burden or unequal treatment.

References:
- https://decilehub.com/base/1-general_questions/163952-on-side-letters-in-8-3-cornerstone-lpa
- https://decilehub.com/base/1-general_questions/163585-is-the-offset-usually-part-of-the-lpa-or-is-that-handled-through-side-letters-do-all-lps-demand-a-100-offset