Service dogs that lead the blind , warn of dropping blood sugar or epilepsy etc ,Yes a trained service dog I think is a wonderful thing. Since its averages about 15 grand for a dog like this to be trained , you should specifically need such a highly trained animal.

I personally feel if you need a dog for a companion, one to emotionally help you feel safe and also basically forces you to go out into the world as dogs need walked , an ESA ( emotional support animal) is a good idea , you don't need a dog that is already trained, Puppies and dogs look to use for love , we look back with same want for love. You can register your own pet as an ESA if he/she meets the qualifications.

Keep in mind whether you eventually ( very long waiting list) receive a fully trained service dog or you find a furry friend on your own.. You are responsible for all the care and vetting... Between food , treats, flea and heart worm medications ,,its roughly about 50.00 a month for my dog , yearly you need routine exams and blood work.

So regardless, having a pet no manner the "Title" is a lifelong and costly relationship.

The link that Sideblinded posted explains all the requirements and differences, its very imformative