You want to know when this gets easier. Ages are useful as landmarks, and they are not a schedule your dog has agreed to.
Read all of this as a broad tendency. A dog who runs early or late on any of it is still an ordinary dog.
12 months: adult body, unfinished dog
This is where the expectation gap is widest. Your dog looks adult, so strangers, relatives and food labels all start treating them as one.
Reduced responsiveness to your cues appears around the onset of adolescence and returns later in the stage. Nothing about that is keyed to a first birthday.
Expect distraction outdoors to still be winning, and leave the long line on.
Expect to be told your dog should know better by now. That comment is about the legs, not the brain.
Keep paying the cues you think are finished. This is the age most owners quietly stop carrying food.
15 months: the house improves before the outdoors
For a lot of dogs this is where the first real improvement shows, and it shows indoors first. The evening settle gets easier before the park does.
Test one thing rather than assuming. Ask for a settle this evening and see what your dog can hold now.
Treat the improvement at home as a reason to practise outdoors, not as a reason to stop practising.
Leave the long line on anywhere your dog has run off before, whatever the house looks like.
18 months: the dip nobody warned you about
Plenty of owners describe a second rough patch late in the stage. Our reading is that it lands somewhere around 15 to 20 months old, and it is common.
The research finding covers the early part of adolescence and does not describe a later dip. We have a separate article on that patch, and this one only tells you to expect it.
Do not read a hard fortnight at 18 months old as evidence that none of the work held.
Check for pain first if it arrived quickly. Pain frequently presents as a change in behaviour rather than as obvious lameness.
Then check what you dropped, and put it back for 2 weeks.
How to use these ages at all
The comparison worth making is your dog against your dog, 3 months ago. Nobody remembers that accurately, which is why writing it down works.
Write 4 lines today: recall, loose leash, settle, greetings. One sentence each on what your dog can currently do.
Date it, and put it somewhere you will find it again. Read it in 3 months.
Pick the line that costs you most this week, and work on that one alone for 2 weeks.
Behaviour change is built from management plus reinforcement, and reward-based training has been associated with higher reported responsiveness and fewer problem behaviours.
What none of these ages will do
None of them hands you a skill you did not practise. Adolescence going quiet gives you a calmer dog, not a trained one.
None of them arrives on a date, and no test tells you your own dog has finished.
None of them is a deadline you have missed. Dogs go on learning well past 24 months old.
Safety note
These ages describe gradual change over weeks. They do not explain change that arrived over days, new fear, growling, snapping or biting. Book a veterinary examination, because sudden behaviour change warrants one, then speak to a qualified behaviour professional.
Today's version, in one line: write the 4 lines, date them, and read them again in 3 months.