Sounds like everyone has really different experiences. My MIL only calls once every 3-4 weeks. But she's always available and willing to help if we need anything, her and DH just don't need a lot of chit chat.
My mom calls me every day sometimes several times a day. And if we don't answer the house phone, she'll call all of our cells. I really wish she'd tone it down, maybe to a couple of times a week. She doesn't seem to have a filter and if she thinks of something to tell/ask me she has to call immediately rather than just wait until we talk again.
I don't know how to talk to her about it. She's not one to take suggestions well and I'm sure her feelings will be hurt and she'll either cry or get mad, yell, and hang up on me. Lately I've just been screening and calling her back the next day. You'd think she'd take the hint! We live in the same town.