looking for honest recs on senior food after my vet quoted me 240 a month for prescription kibble and i need a real conversation about whether thats actually necessary

My cocker Maple is 9 and just had her senior wellness done. Bloodwork is mostly fine, kidney values are at the high end of normal but not in disease range, vet called them "early indicators." She recommended switching to a prescription renal diet preemptively and the cheapest version of it is $240 a month at my dose for a 28lb dog. That is more than my electric bill.

Im not anti-vet, my vet is genuinely good and i trust her, but im also a first time dog owner trying to figure out where the actual line is between "necessary medical intervention" and "this is the conservative recommendation a vet has to make to protect themselves." Im not interested in raw vs kibble flame wars and im not interested in anyone telling me to ignore my vet. What i want is to hear from people who have been in this specific spot: senior dog, slightly elevated kidney numbers but not in failure, and you had to make a real decision about food.

If you stayed on the prescription, was it worth it. If you switched to a regular senior or lower phosphorus food instead, what did you pick and how did the next bloodwork look. If you went the home cooked route, did you actually consult a real veterinary nutritionist or did you wing it from blog posts. Im trying to make this decision with my eyes open and not based on either fear or budget panic alone.