For some people they are not a luxury. My very ill and depressed father has four dogs, three of his own and one end of life foster. He never meant to have four, he only ever wanted one, he just accidentally collected the rest.
Before he got the first dog he would sleep for days on end, rarely washed, rarely left the house, never spoke to anyone etc.
He now walks for two hours a day, has a whole new group of friends and has to get out of bed to see to his dogs. He can't afford them, per se, but we have an unspoken agreement whereby I pay for any emergency treatment the dogs might need so they save on pet insurance. I also help out with other essentials such as replacing the PC he needed to keep going the business he set up in order to fund his dogs.
Those dogs have literally saved his life.
We are fortunate in that we can afford my dogs without going without, we have a great network of people who provide holiday care for us, although Devil Dog ends up in kennels sometimes, depending on how many arch nemesis he has collected through the year and whether there is space anywhere where won't end up eating or being eaten by another resident dog, we are never short of carers for Whippy or fat cat. I'll happily leave them alone to go to the cinema (not so much soft play, but that is more because I despise soft play) and cab leave them for whole days occassionally knowing that my Dad will come round and walk them for me half way through the day.
We are going away in August, Whippy will be going camping with my parents, Devil Dog may or may not go into kennels, depending upon whether his latest enemy at the foster co-ordinators house finds a home between now and then. We are away again in Sept, that will be more difficult as I will need to fund kennel space for my Devil Dog and two of my Dad's, the other two have their own dedicated babysitters and Whippy can go to our foster co-ordinator, so that weekend could potentially cost me another weeks holiday, but they're worth it to us. The neighbour will feed fat cat and the fish.