I have met many 'seniors' who miss a much loved pet, and would love another, but are concerned they will outlive it, and have noone to care for it .
Animal Aid in Coldstream, Vic. (www.animalaid.org.au) has a special program to encourage 'seniors' to give a 'senior' animal a new home. There is a reduced adoption fee, and the animal is carefully matched to the new owner's situation. A great program.