'how long since' is correct and usable in written English.
It can be used when asking about the time elapsed since a particular event or action. For example: "How long since did you last visit your grandparents?".
How long since he'd eaten?
"How long?" "Since your father got sick, Chino".
"This is the first time in how long since the Brewers went to the playoffs?" asks one diehard fan, rhetorically.
The same XI for Australia - how long since they played the seam team three matches in a row.
Social Monitor also issues recommendations about whether you should remove an app based on privacy level, developer reputation and how long since you've used it.
But time after time, no matter how long since I last tasted it, Hook Norton seems to me rich and balanced as no other beer on earth.
So he and a team of researchers examined 41 species of mammals and checked for correlations between their phylogenetic age--how long since they had split from their most recent common ancestor, as indicated by DNA analysis--and their sensitivity to logging.
Twenty five of these reported NSSI but did not respond to self-injury recency (e.g. how long since last injury) items so were not included in these analyses.
They've been carrying the majority of our offense for how long now?" Since Jan . 5 the day Muckler put Hlavac and Dvorak with Nedved to form the line.
You've finally got your heart's desire, a Southern President, after how long now?" "Since 1849".
The participants were also asked if they vomited after eating, and if so, how often (daily, several times weekly, monthly and occasionally) and how long time since the last episode of vomiting.
