How soon...

How soon should I look at taking over a neighboring C3 country. Just started playing this week and while expanding my empire sounds fun I don't want to jump the gun and drown in complications.

It's not a good idea to go taking over other countries until you're sure you can manage your existing country responsibly. When your education index is around 200, when your healthcare, transportation and social security indexes are at or above 100, when every single corporation in your country is run by a CEO, and when employment is around 95%, then it might be a good time to start expanding your empire. It's great to add countries to your empire, but you should make sure that each country is properly developed before taking over another one. Even just one highly developed, economically stable country, is still better than several countries which are all equally mismanaged and bankrupt.

on the other hand, taking a c3 will help your country by transfering people, like teachers, doctors, etc. Keeping temporaily for that reason and deregistering once its usfulness is done. If you plan on this coarse of action, keep just enough weapons to get the job done. Armies cost alot of money to maintain, and you may want to consider selling off any unused weapons once your mission is complete. Once you have grown and have a good finance, then you can start gathering a small army to keep, keeping in check your finances as you grow your army.

I asked this same question awhile back. I think it depends, in part, on what your plans for that country is. If you intend to keep it, you may want to have enough defensive forces ready to assure a chance of keeping it. As well as enough cash on hand to pay off the war debt and to repair the devastation you visit upon the target. Looks like it takes awhile to return the country to a firm economic foundation.

Homerdome has already covered the "catch and release" method.