For years I did what everybody does. Fly into the capital, spend four days there, maybe take a train somewhere for a night, fly home.
About five years ago I started deliberately basing myself in the second city instead, and I have not gone back to the old way.
What the capital does to itself
Capitals absorb a disproportionate share of visitors, and the parts that visitors use adapt to them.
Restaurants near the main sights cook for people who will not return. Prices in the centre reflect what visitors will pay rather than what residents will. The people you interact with in the tourist quarter are doing a job that involves being pleasant to strangers all day, which is not the same as ordinary contact.
None of that is anybody's fault. It is what happens to any place that receives more visitors than it has residents in a given district.
The consequence is that the experience is real and it is an experience of the visitor economy rather than of the country.
What the second city has instead
Enough infrastructure to be comfortable. Trains, hotels, restaurants, people who deal with foreigners often enough not to be startled.
And not enough visitors to have reorganised itself around them. The good restaurant is full of local people. The market sells things people cook with. The prices are the prices.
Second cities also tend to have a chip on their shoulder about the capital, which produces a lot of local pride and a strong sense of identity, and people who are pleased that you came.
That last part is not sentimental, it is practical. People who are glad you are there are more helpful, and a great deal of what makes a trip good is what people tell you.
Getting there is easier than it used to be
The main objection is flights, and it has weakened considerably.
Many second cities have direct international connections now, often from budget carriers. Where they do not, the domestic connection or the train from the capital is usually a couple of hours and cheap.
And arriving into a smaller airport is a much better start to a trip. Shorter queues, shorter transfer to the centre, less of the disorienting scale that large hubs have.
The cost difference is substantial
Consistently, in every country I have tried this in, accommodation is significantly cheaper for equivalent quality.
Food, more so. The gap between a good restaurant in a capital's centre and a good restaurant in a second city is often a factor of two.
Which means the same budget buys a longer trip, or a better one, and that difference compounds over a fortnight.
Where it does not work
Being honest about the exceptions.
If you are going for specific things that only exist in the capital — a particular museum, a collection, an institution — then go there. Some things are not distributed.
In some countries the second city is genuinely much less interesting, or is an industrial centre with little to look at. This is worth researching rather than assuming.
And for a very short trip, three days or fewer, the extra transit to somewhere less connected eats too much of the time.
How I choose now
I look at what the country is known for and then find where that actually happens, which is frequently not the capital.
Food traditions are often strongest in a particular region rather than in the seat of government. Music too. Craft industries, similarly.
Then I look at whether the place has enough of a university or a business presence to support decent hotels and restaurants, because that is what makes somewhere comfortable without making it touristic.
A city with a large student population is nearly always a good bet. Cheap food, late opening, a lot of young people, and enough churn that a stranger is unremarkable.
The compromise version
If you want the capital's sights and the second city's texture, the arrangement that has worked best for me is basing in the second city and taking a day trip to the capital rather than the reverse.
You see the things you wanted to see, and you sleep and eat somewhere that is not organised around visitors.
Trains between major cities in most countries make this straightforward, and the day trip has a natural discipline to it — you go, you see the specific things, you leave, and you do not spend four days drifting between them.
What changed for me
The trips became less about seeing and more about being somewhere, which sounds like the kind of thing people say and is a real distinction.
I remember conversations from these trips. I remember specific meals. I remember what a Tuesday afternoon was like in a place, which is not something I ever got from four days in a capital moving between sights.
And I have gone back to two of them, which I had never done anywhere before.