I was thinking that it's an expensive hobby (an opinion his wife, who keeps the books, probably shares).

It's an expensive hobby, so most of the ones I know collect reproductions.

In a sense, the rental system makes art an expensive hobby.

A less expensive hobby would be to trace the long history of this little place through modern stamps.

"You didn't tell me horseback riding was such an expensive hobby."

Orwell questions the idea that buying or reading a book is an expensive hobby.

"Documentary making is an expensive hobby but some stories need to be told."

I rather envy anyone who can afford to turn scientific curiosity into an expensive hobby.

Most people didn't even have a car, and golf was a very expensive hobby available to only a few rich people.

It's not an expensive hobby if you do all the restoration and rebuilding yourself.