Too many variables not in evidence to make an informed response.
Is cctv or guards enough for security of my organization or do I have to adopt a whole security system?
It depends on your choice which type of security you want for your organization' s security. Installing a whole security system gives you overall security includes Cctv and guard security.
Not enough also have to adopt guard security.
Only you can choose. If you wanted to put a security system in your apartment, then you could do something simpler than the whole system. But if you want to put a security guard in your organization, then I think that you should bother a little more. If I were you, I would consider Ajax. I heard a lot of good things about it, then I decided to try it myself and was satisfied. You may think that the prices are a little expensive, but it's worth it. You can see all the info on their website https://ajax.systems/ , there are just the prices. Maybe they won't seem so high to you.