I have a friend who I have known for years - we worked together in the mid-2000s.
I have given her a lot of help over the years in applying for jobs (she asks me, I don't instigate this) and have always been happy to do so. I did notice a good two years ago that she only really contacted me when she wanted a job application doing but we've been good friends for ages - weddings and significant birthday parties and so on so I ignored it.
Then my life went into freefall about a year ago. I heard nothing from her. As the months went by I decided I was sick of being used, had a facebook cull and heard nothing. She then re added me after I had a conversation with a mutual friend where I alluded to the fact I had felt used.
Anyway I haven't seen her since but we are on good terms when we speak which is rare.
Just had a message asking for help with a job app 
Now, I wouldn't mind at all if we'd been in very regular contact and she often did me favours and helped but when I desperately needed friends she was nowhere - so I'm not helping on this one.
WIBU to ignore it? Or should I reply saying no and briefly say why? (I don't want an argument by the way.)