Dog professional here...
It is a huge committment - its another toddler for the next 14 years in some respects.
But without the ability to take that toddler everywhere or easily find daycare, or understanding responses from others... ie..
'Im sorry we have to cancel todays BBQ because our DS is terribly poorly'... most folk get that.
'Im sorry we have to cancel todays BB because our DOG is terribly poorly '.... most folk don't get that at all.
or 'We'd love to come we will have to bring the DC's with us, is that ok'... pretty much yeah (except weddings).
'We'd love to come we will have to bring the DDog with us is that ok'... pretty much 'hell no'.
And thats for a normal well mannered dog.
Consider that many behaviour 'problems' are in fact totally normal - separation anxiety, barking at weird shit, crapping in the house, these are actually normal dog behaviours that WE don't like. Non dog owners and even some dog owners are wholly intolerant to that stuff... and that can be a real pain in the bum repeatedly being told 'oh just leave him he'll get over it' or 'oh just train him' as if that can be done over night etc.
Costs.. insurance, yes, doesn't cover everything. Training classes and behaviourists (yes i WOULD factor that in!), lots of money, around £70 to 100 for a course of training classes, between £150 to £300 for a behaviourist to visit and do a behaviour modification plan.
Food - well I feed 5 for around £150 a month but thats CHEAP.. because I get trade discounts on food and feed a raw diet. I would budget half that on commercial premium quality food for a single mid sized dog (including treats). Cut corners, get more poo, more pong and more vet bills.
Gear - leads, collars, coats, harnesses, gadgets and gizmos (doggy 'fitbit'.. £150. Pet camera to watch your pet whilst you are out, £45 to £150. Crate, £50 to £100, dog beds etc etc.
Increased heating bills because your bloody french hound wants to spend all day outside staring at the weather whilst you sit with the door open freezing your titties off... or thats just mine perhaps.
Puppies... are HORRID. There is a reason they are cute, its so you dont kill them. They bite, they upset children, they shit and piss all over if you BLINK, they need to be with you all the time like a newborn does, but no ones giving you any presents or chufty badges for producing a puppy like they might with a baby.
On the plus side, by aroun d8 months thye should be properly toilet trained unlike the human equivalent and you can prevent them reproducing surgically at 2 years old. Marvellous.
If you get the right breed from the right breeder or reputable rescue it can be a ton of fun and very rewarding.
Get it wrong, it can be a miserable and expensive experience for all concerned and ultimately its gonna be the dog that suffers the most, because it always is.
My advice if you do decide to go for it is to get a trainer/behaviourist to help you find the right breed/type for you and set you on the right path BEFORE errors occur.