Texting an ex girlfriend is one of those topics that seems to come up quite a bit and there is a good reason for that. For some people, texting has pretty much replaced phone calls and even for those who are not that into texting probably still send at least a few a week. So, it's not unlikely that the idea of whether or not you should text an ex girlfriend to try and win her back has crossed your mind. There are probably lots of opinions on this, and I don't really think that there is necessarily a one size fits all kind of answer for this.
My opinion is that it can help, but only if you go about it the right way. You don't want to start texting her night and day, that is a sure fire way to get her ticked off at you. It might also make her start to wonder about whether or not you are turning into that stalker ex boyfriend that all women have a pretty natural fear of. So, in that situation, it definitely wouldn't help you at all.
So, when is it good to text your ex girlfriend if you want her back?
Usually after you have started to talk to her again face to face. You could try and send her a text or two before you start talking again to her face to face, but most of the time, that is going to end up being the best time. You want her to already have some feelings of wanting to hear from you before you start sending her messages. Even then, you really should go about it sparingly.
Another good situation to text your ex girlfriend is the occasional, what's up, kind of text where you are just trying to touch base with her. That's not really going to be something that ticks her off and most likely, if she doesn't want to reply to you at that moment, she just won't reply and that will be that.
Rather than trying to use text messages as a way to get her back, you should use them as part of your overall strategy and a small part at that. You'll most likely have a much better chance if most of your interactions with her are face to face. You can do a lot more attraction and rapport building with someone when you are actually with them as opposed to just trying to build up attraction and rapport through words on a little screen.