The only other times would be what you agreed to in your lease or rental agreement. If there was nothing you do have to let them in with 24 hour notice to make repoairs or show new prospective tenants if you are moving out, if you refuse them entry, they can enter with that 24 hour notice.
Simply google lanlord tenant law for CA and look under the section of entering your apartment.
good luck with working thing sout
You need to read your lease as indicated, but also read the Landlord Tenant Law for North Carolina. I did a quick search and found the link below. I don't know if there have been revisions, but I would start here.
If he or she perceives there may be a problem, I assume they can enter (say a fire or leak). I would further assume that they should give you a courtesy call if they need to get in for some maintenance issues.
If you feel the landlord is entering without reason or the right to do so, then I'd have a discussion about this right away. You should have the right to "peaceful" existance - and your privacy should be respected.
Once again - read your lease for any verbiage regarding gaining access to your apartment.