Where do you draw the line between linking up again with an old fling again or not...?

I know that getting back with an LTR or a girl who disrepected you is a no go, but picking it up where you left with a plate that you've slept with only a few times is usually no problem. I've had girls hit me up after 6 months+ and hooking up then is no problem because there are literally no emotions left.

However, I have a situation atm; FWB I was seeing for 6 months called me yesterday (I was asleep so I didn't answer), after 2 months of no contact (last time she wanted commitment, I said no --> she did some very typical girly petty things, so I removed her from my life completely).

I was somewhat hurt but it didn't take me too long to get over her and I've been seeing other girls since then.

I'm 20 & she's 18 and she knows very well that there will be no LTR (especially considering the way she acted when things ended last time).

I'm confident that I could stay emotionally detached and only "use" her for sex.. ooor I could be completely wrong and end up hurt again.

In a situation like this, is it worth linking up with her again?