If your piano hasn't been tuned in the past couple of years or more, a pitch-raise may be required. This is also referred to as a "tension adjustment" and is necessary before the piano can be fine-tuned.
A piano that is very out of tune will not hold a tuning as well as one that is regularly maintained.
In some cases, if the piano has been seriously neglected or damaged, it may not be tunable. In some very old pianos (100+ years), tuning at standard pitch may not be possible and tuning at a somewhat lower pitch may be advisable.