"reasonably careful" is a correct and usable phrase in written English.
It means exercising a level of care that is logical and appropriate in a given situation. Example: The driver was found at fault for the accident because he was not reasonably careful while making a left turn at the busy intersection.
It's a reason to be glad that an earlier general was reasonably careful about his (still alleged) affair — not to give a later one license to cheat.
It is a reminder that the Canadian political system got an incomplete renovation 36 years ago and the only reason the whole thing hasn't collapsed yet is because everyone's been reasonably careful not to rock the casbah the odd sovereignty referendum aside.
Harvey's mechanics do not seem to put him at an elevated risk of injury, and the Mets have been reasonably careful with him.
Jewellery designer Arabel Lebrusan, however, is happy to show her wares to customers in public places as long as she's reasonably careful – after she withdrew from her Sloane Street store due to maternity and also the challenging economic climate among other reasons, she now works from home and sells online.
These are reasonably careful parents who do nothing risky.
A person is negligent if he or she does something that a reasonably careful person would not do in the same situation or fails to do something that a reasonably careful person would do in the same situation".
The vegetable oil reactivity has a direct effect on most of the polymers' properties, which can be reasonably predicted by careful choice of the vegetable oil.
40, 124 The traditional approach to syndrome nosology involved the careful characterization of reasonably consistent phenotypes, reflecting genetic homogeneity.
Be careful that your items are reasonably priced, otherwise you may have a hard time selling it.
Who cares, one might reasonably ask.
But as long as the platters are reasonably intact, it's just a matter of careful dissection and re-mounting the drives.
