Platform height is where you stand. Working height is where you reach.
Manufacturers quote PLATFORM height, the height of the platform floor. WORKING height is the platform height plus about six feet, being the reach of an average person standing on it.
So a 26 ft scissor lift gets your hands to roughly 32 ft. If the fixtures are at 28 ft, a 19 ft machine gets you to about 25 and will not do; a 26 ft machine will. Buy for the height your hands need to be.
Then check whether height was even the constraint
Can the machine stand directly under the work? If yes, a scissor lift is the cheapest way there. If something is in the way, whether a roof, ductwork, stacked material or a building edge, you need a boom lift, and probably an articulating one.
How wide is the narrowest point on the route in? A 19 ft narrow scissor lift is about 30 inches wide and fits a standard doorway. From 32 ft up, decks are typically 46 inches or more.
What is the ground? Concrete or a compacted improved surface means a slab machine. Anything else means rough terrain.
Reach matters more than height on a telehandler
For material handling the question is rarely how high, it is how far forward. A telehandler's capacity drops as the boom extends, so a machine rated 10,000 lb close in might be rated a fraction of that at full reach. Read the load chart, and note that it changes depending on whether the stabilizers are down.
A worked example
Replacing high-bay lighting at 28 ft in an occupied warehouse, on a finished slab, through a standard double door. Working height needed: 28 ft. Platform height needed: about 22 ft, so a 26 ft machine. Ground: finished concrete, so slab. Indoors and occupied, so electric. Width: check the door, and a 26 ft machine at 32 inches will go through.
That is a 26 ft electric slab scissor lift, one of the most commonly rented machines in Texas, and the estimator on this site will price it for your city in a few seconds.