John Tye Piano Tuner
A routine 6-monthly tune takes roughly an hour, although I like to take a little longer if I get the chance.

Pianos tend to drop in pitch during the winter, and rise again in the summer, due to the combined effect of temperature and (mostly) humidity. Unfortunately treble strings are much more affected than bass strings, so the piano goes out of tune. This is the origin of the 6-monthly tuning. The extent of the problem depends on the design and condition of the piano. This will matter to you more if you play with certain other instruments. Heavily used pianos can easily go out of tune in 3 months.

Pitch raising
Raising the pitch from 439Hz to 440Hz is no problem, and does not class as a pitch-raise.
A small pitch-raise from 434Hz to 440Hz (about ¼ semitone) can usually be accomplished in one visit, but requires two tunings because the piano settles during a pitch-raise. This therefore takes at least two hours.
Raising the pitch by any more than this requires two visits really, allowing the piano to settle between visits.
A very out-of-tune piano that has not been tuned for years is likely to be not only flat but at an uneven pitch. This requires an initial levelling with or without a pitch-raise followed by a two-stage tuning similar to a pitch raise. This therefore takes about three hours. A follow-up visit is required after it has settled.

The other reason for out-of-tune pianos is slipping of the tuning pins (the pins around which the string is coiled). The wrest plank (that holds the tuning pins) shrinks as it dries out (and, I have to confess, to some extent gets worn with repeated tuning). This is fixable to an extent (but chargeable), and I try to avoid turning pins any more than necessary (for which an electronic aid is useful).

Strings are stretched close to their breaking point in order to get the best tone. They occasionally break, more on some pianos than others. Even if it breaks while I am tuning, it is still your fault, and you will have to pay to get it replaced.
Electronic Tuning Aid
I use this to check my consistency, and to give a good equal temperament. An aural check will always be allowed to over-ride it. The tuner is especially useful if there are distractions or for a large grand so that I can use my ear plugs. The electronic tuner also has unequal temperaments, so if you want your piano tuned as Mozart would have done we can choose a likely temperament. I also use an electronic device in preference to a tuning fork which can have quite a significant error without any warning.
Quoting, etc.
If I pay a visit just for quoting, assessment or valuation, somebody has to pay, and that person is you. If you subsequently have the piano tuned by me I will refund half the fee. If you have significant repair work done as well I will refund the whole fee. You will probably gather that I have been caught out too many times by people asking for a quote and getting a free valuation with no prospect of follow-up work. Valuations are very approximate anyway; I come across people paying very over-inflated sums for a poor piano that I can then do little with. That is why I offer an assessment service, but only for local purchases. I cannot evaluate an antique value; you need an auctioneer for that.

first-time or ad-hoc tuning, at least £75
subsequent annual routine tuning close to Northampton £70
small pitch-raise and tuning close to Northampton £95
levelling, pitch-raise and tuning in one visit, up to £115
call-out fee £50