I can only speak from my own experience and I'm also interested to know what other affiliates would do in this situation.Do you then just relaunch again and again, until the algo succeeds in giving you a solid CR and therefore a campaign with better longevity?
It depends. I use direct-link for most of my campaigns (99%, because I'm lazy) & my main affiliate network is Monetizer. I'll look at the stats of the offer on Monetizer's "snapshot" first before I decided whether to relaunch or not. If it's a new offer and/or the CVR looks promising, then I might give it a 2nd or 3rd try.
The only time I would relaunch a campaign again & again is when a working campaign begins to lose it's "momentum",i.e when traffic begins to slow down.