Can I get a jump?

Usually Greg would like it if I called him in the morning and asked him to come jump me. But for the past 3 Mondays like clockwork I head out to my car to head to work and my car wont start. The past 2 weeks Greg's been at work so I called on the front desk (I mean we do pay HOA fees they can do something for me) and the next week I asked out nice neighbor, and this week thankfully Greg was home. I don't know what is wrong but if I don't drive my car for more than 24 hours it decides it doesn't want to start. I don't know its just annoying and I really don't want to pay to have anything fixed, so far the jumps have worked so we might just have to plan ahead or I might have to start driving my car on Sunday.