For me it’s usually flights and accommodation. When I look back at my trips, those two often take around 60% of the total cost.

Most of my trips are more vacation-style, so I usually spend more on comfortable hotels or resorts and less on shopping.

I’m curious how it looks for other travelers here. What usually takes the biggest share of your travel budget?
Flights, accommodation, food, activities, or something else?

Is this a serious question or are you trawling for content?? If serious - that is pretty much unanswerable - it entirely depends on the specific trip. Destination, type of trip (am I attending the Opera in Milan or hiking the Cotswold way or laying on the beach in Baja?), transport (am I driving to Yosemite or flying to Singapore?)

Every trip is different

Depends how long the trip is. For a short stay the plane ticket is the most expensive. For a week or a month away, then obviously the lodging is the most expensive item.

Maybe my trips are a bit different. Looking back at my past trips, flights and accommodation almost always end up being the biggest expenses for me, whether it’s domestic or international. And, most of my trips are around 3 days to a week.
Do you usually make different proportions depending on the type of trip?

Of course. Different trips can have vastly different proportions.

Agree with all of the above. I use an app called Trail Wallet and it’s interesting sometimes to see how the different expenses end up applied. I do budget for a trip in advance, use the app while on the trip, and then take a look.

Do you usually make different proportions depending on the type of trip?

Of course. Not so much "type of trip" rather length of trip as I already mentioned. But to clarify my point... If I flew to Mexico and stayed 3 days - my flight would cost $800 and my lodging would cost $300. If I flew to Mexico and stayed 3 weeks - my flight would still cost $800 but my lodging would be $2100.

These two expenses together are always much larger than any local transportation, meals, shopping, or activities I might do during the trip.

I also keep an electronic ledger, similar to the app you mentioned.
At the beginning of each year, I set a total travel budget for the year. Then I track my travel expenses and categorize them in the ledger so I can see how the spending is distributed.
When I reviewed my records while setting this year’s budget, I noticed something interesting. The overall pattern has been surprisingly consistent over the past few years. No matter where I traveled, whether domestic trips or international ones, the proportion of my travel expenses stayed almost the same.

I see. In your examples the proportions change mostly because of the trip length.

In my case it stays fairly similar because most of my trips are either around 3 days or about a week. I also tend to keep accommodation within a similar price range each time, ~100/night/2 people.

For flights, I usually travel within nearby regions rather than long-haul trips, so the airfare tends to stay within a fairly predictable range as well.

Because of that, flights and accommodation usually end up taking a very similar share of my total travel budget each trip.

Generally, I prefer a comfortable travel experience, so I tend to spend more on airfare.