I can only give you my personal opinion , I have 2 middle aged greyhounds , there simply living out there retirment here with me, I swapped them both from dry food to a mainly raw chicken diet about 2 yrs ago & I am more than pleased with how they look
I wouldnt feed dry now , I dont have to worry about to much protein & additives etc or switching to a senior food, I dare say some of the '' premiem'' dry foods are good but for me its not the cost of the food its the fact that they look better & smell less & poo very little