I grew up with dogs and moved out of my house when I was 18. Going from house to apartment to house to apartment (whatever I could really find that made me happy) was not conducive to a dog. Finally in 2002 I was gung ho on getting a dog but then realized that I do believe having a dog in an apartment may not be fair. It is not that it cannot be done but for me, I wanted to wait until I bought a house. That was my own personal hang up. I got a cat.
Many many years later I got a house and I got a dog. I was not looking for the particular breed that I got but there were YouTube videos of her online that made me realize that she was indeed the perfect dog for me. I've had her 10 months now and here is what I've figured out and yes, I am quite attached to her.
I could easily travel for up to 5 days and not worry about my cat. I cannot do that with a dog. Every time someone springs an idea to go away on me I have to look to see if I can board her. It's $40 a day/night to board my dog but the facility is remarkable. If I want to leave some place late Friday night on a whim and not come home I cannot do that unless I can bring my dog. I can't just bring my dog everywhere. This is the biggest hassle for me overall that was not even considered when I got the dog because my life was different 10 months ago. Even still, it is something you need to consider.
I work from home, which is nice, but if you get a dog you never know what it may do when you're not home. My dog was entirely different when I got her than how she is now. She is coming into her own and she knows this is her house. No dog trainer will appreciate that comment but it is true. Recently there has been some unwanted behavior so I have to crate my dog when I go anywhere, even for 30 minutes. I'm hoping she'll get past it. I caution you to look at the breed because my dog does what she does because she has separation anxiety which is a known trait in American Staffy dogs and pitbulls, I have a staffy.
You have to consider that your dog will be alone for 8 hours a day minimal. Again, cats don't tend to give a crap but dogs do.
Dogs may want to pee in the middle of the night. Dogs don't care if you have the flu and you're puking everywhere, if they have to go they have to go. Dogs need baths, this is either an additional cost or something you have to do yourself depending upon the dog. Long hair dogs shouldn't be bathed in a household tub because of all the hair. In the summer outside baths are nice though.
Dog food, if you give two craps about the dog, is not cheap. I feed my dog Blue or Blue Wild. That is $28 for 18 lbs or $52 for 24 lbs of the Wild variety. That is not cheap and figure 18 lbs every 10 days give or take for a 40 lb dog (that is my scenario).
On the most positive side, my dog is the reason I get out of bed every morning. If I don't she'll pee wherever she wants. It is not as though I don't really want to get out of bed but I don't have the luxury of just staying in bed all day. I have to at least go outside. If you're in an apartment you'll have to get dressed and go out. At least in my backyard I can look halfway unkempt and still let her out. In the winter at 6 am it could be 20 degrees. That sucks but guess who has to pee? That is right! The point is, having my dog has really been good for me. Though it can sometimes be a hassle, the benefits of having a pet that really does care if you're around is cool. My cat cares when I get home after a 5-day trip but otherwise, he's chill as long as he gets food and water.
Most people will say dogs are expensive, require a lot of attention and there is never really a way to get a vacation from them unless you pay to board them. This is all very true. My dog likes to play and has gotten herself hurt before. She's been pretty problem free for the most part but annual shots, check ups, food, grooming, and of course everything I spoil her with is not cheap. Again though, I feel lucky to have found her ... she's a giant stupid head.
I personally looked for a dog that was 1+ year because I felt like it was easy to get a puppy, they go like hot cakes. My dog is going to 2 in August, I think or I guess ... she's got some puppy in her but she's generally pretty chill. I do take her out a lot, she goes a lot of places with me and we hang out at the dog park frequently.