How do you decide when to implement a "renal diet" (i.e., restricting electrolyte and/or fluid intake) in hospitalized patients with renal impairment?

I think about this from several perspectives:

First, what's the severity of the renal impairment? Generally, I consider electrolyte abnormalities like hyperkalemia and hyperphosphatemia more likely to occur when the eGFR is <60 (for hyperphosphatemia, it might be more evident when the eGFR drops bel...