The phrase 'it may vary' is correct and usable in written English. You can use it to refer to situations in which something is not fixed or consistent, and could be different from one situation to another. For example: "The cost of the new product may vary, depending on the quantity purchased."
The price is advertised as $50 — it may vary based on location — which is more than the new $39.99 model.
Depending on its source and age, it may vary from yellow-green to dark brown.
This was done to maintain a more consistent sample size, as it may vary substantially when using time-varying covariates in analyses.
It may vary for different current densities.
It may vary from six months to six years.
It may vary by up to one size in length".
The regret is real, though it may vary from one manuscript to the next.
This lasts for about 9 days, although it may vary by 2 or 3 days.
Outwardly, it may vary a little, but the spirit and heart are the same.
The slope may be uniform over the entire field or it may vary from part to part.
Getting a sense of the depth of the problem here -- and how it may vary from other communities in New Jersey -- is difficult.
Thanks to Ludwig my first paper got accepted! The editor wrote me that my manuscript was well-written
Listya Utami K.
PhD Student in Biology, Bandung Institute of Technology, Indonesia