The phrase "appreciable length of" is correct and usable in written English.
It can be used to describe a length that is significant enough to be noticed or measured.
Example: "The project took an appreciable length of time to complete, exceeding our initial estimates."
Alternatives: "considerable length of" or "substantial length of".
It's the only New Year's resolution I can remember keeping for any appreciable length of time.
That comment is heard whenever actively managed stock mutual funds beat the Standard & Poor's 500-stock index for any appreciable length of time.
I don't forget for any appreciable length of time that I am speaking to prisoners.
The highest classification placed on any appreciable length of road in Korea by Eighth Army engineers was for a gravel or crushed rock road with gentle grades and curves and one and a half to two lanes wide.
These organisms survived for an appreciable length of time [35].
Certain free radicals are stabilized by their peculiar structures; they exist for appreciable lengths of time, given the right conditions.
His fast, warped work -- cut into tracks of appreciable length instead of club tunes that become snores on the home stereo -- never fails to make you feel as if you're on something.
Moreover, his account does not touch a remaining problem that he himself notes (1628, Rule VII, p. 7): Deductions of any appreciable length rely on our fallible memory.
There were no appreciable differences noted in the age, sex, length of follow up, pre-treatment, the severity of symptoms before treatment and number of intra-articular injections given per course in each X-ray category identified.
Despite few participants, the depth and length of discussion conveyed an appreciable volume of rich data.
These studies, taken together, raise the question of whether there is an infectious component in disease previously thought to be unspreadable, but it bears repeating that it is not clear whether bacteria added to our microbiomes from the environment establish themselves on or in our bodies for any length of time — and, if they do, whether they have any appreciable effect on our well-being.
