There is a lot of nuance to what happens and when. If you "ipfs add" a file, ie take a local file and add it to ipfs, the default is to also pin it. This is mo

There is a lot of nuance to what happens and when. If you "ipfs add" a file, ie take a local file and add it to ipfs, the default is to also pin it. This is most likely what you want. If you just fetch or cat a file, it will still put it in the local store but it will not pin it. However you still could serve that content until it is GCed from your local store. Pinning is the action of getting the content into your local store and preventing it from being GCed in the future. All that said, your point is still valid. Viewing a file is enough to also make you serve that content, and it's very non obvious when you are and when it will be purged.