I'm currently working on my fifth novel, all of which feature the same main characters. There are four kids in the family, so different books key in on a particular kid(s) as the main character, but nonetheless, I use the same characters repeatedly. I've found that I've developed an attachment to the characters and feel comfortable writing about them. I feel as if I know them and it's almost as if they've become old friends in some respects. I have other plans that will involve using other characters in the future, but I still see myself continuing to use the Taylors for some time. What drives you in your selection of characters?
I don't write series, so I don't bother with the same characters. Mine are new each time out - each story is a standalone. I've said it before - characters just seem to pop into my head. Within a few minutes (usually), I have a situation for him to deal with. He's my character.
Since all my characters exist in the same universe, they tend to pop up again from time to time. Though if I can't think up a solid timeline of events they can participate in, they're usually killed off or only referenced to be somewhere else.
If it is a series, then yes i will keep the same characters. but when I switch series, I switch characters, it doesn't feel right for me to run a couple of series with the same character. the same with stand alones, they have different characters.
If I've read characters that I adore, I will read other books in the hope they'll appear at various points. That's definitely informed my writing choices and right now, I'm working on a few different series in the same world so will be including cameo appearances and cross overs. But, I but won't do so forever. Eventually I'll set my mind on developing a new story with new people in a new place, because that's another enjoyable part of writing I don't want to miss out on and, ultimately, we have to say goodbye and let our character's stories end at some point...even if we don't want to! In your case, since you started with a large cast it makes sense that you'd keep writing - there's more mileage in a story about 5 people vs 1, after all. As long as you're enjoying it and the story is working, why not?