Seven league boots are one of the most powerful and useful items in the roguelike game
ADOM, and many players consider them one of the most important items in the game, readily worth spending a
wish on. They dramatically reduce the time it takes a
character to walk by lowering the energy cost of movement.
ADOM uses two systems of movement: The first, used in generic dungeon levels, town levels, and wilderness locations is a turn based-system called "Discretized Timing". Discretized timing operates on the principle that the character and every monster in the current level gets a number of energy points each segment- every ~3.5* seconds in ADOM- equal to its speed, which are then used to perform various actions. Whenever a creature gains energy points, the game checks to see whether the monster has enough energy to perform its next action: if it does, the monster performs its action and the game subtracts points from the monster's current energy pool; turns, therefore, begin as soon as a character has finished an action: a turn being a prompt for a character to begin perform his next action, be it resting, attacking or moving.
The other system of movement is used only in the wilderness map, and it simply adds time to the game's clock- about 60 minutes for walking over plains, five hours for climbing mountains with a climbing set.
The base cost of one movement action in ADOM is 1000 energy, which means that an average character with speed 100 can take his turn once every 10 segments. While wearing Seven League Boots, this changes, depending on whether they're cursed, uncursed or blessed. They also drastically change the time it takes to move in the wilderness: blessed boots decrease travel time by a factor of six.
+-7-Boots--+-Move-+--Plains--+---Hills--+-Mountains-+
| None | 1000 | ~60 mins | ~90 mins | ~5 hours |
| Blessed | 500 | ~10 mins | ~15 mins | ~50 mins |
| Uncursed | 750 | ~20 mins | ~30 mins | ~100 mins |
| Cursed | 1200 | ~2 hours | ~3 hours | ~10 hours |
+----------+------+----------+----------+-----------+
(Note that all times listed, though not action point costs, vary from turn to turn while playing.)
The halving of movement in blessed boots cost acts like a doubling in speed specific to movement only, but this is still an incredible boon: It gives an effective speed of 200 to a character with 100 for the purposes of running, and makes any other movement boosts even more wonderful- a character with Athletics 100, born in the month of the Raven will have a total of 118 speed, thereby giving him the 500 energy points in only four segments: making him two-and-a-half times faster than a standard character. For this reason, items that increase speed are also highly valuable while wearing the boots, as is keeping away from satiated and bloated satiation levels or burdened and higher encumberance levels. Unfortunately, it also appears that satiation levels decrease twice as quickly-- the character gets hungry twice as fast.
As the boots don't actually grant high speed, the character will still attack, quaff potions, shoot, kick, and do every other action at normal speed; if a player wants his character to move faster in every way, Boots of Great Speed give a character +30 speed: however, they are non-guaranteed artifacts (can't be Wished for), auto-cursing (when you put them on, you can't remove them), and corrupt the player extremely quickly. It is generally a far better idea to wear the Seven League Boots rather than wearing these: if generated, they should be put to some other use.
Another wonderful point is that characters heal by the turn, not by actual game time: this means a character in blessed Seven League Boots not only walks twice as fast, but also heals twice as quickly and regenerates power points for spellcasting twice as fast (as long as he keeps moving).
Wishing for the boots is possible, and the most common way of getting them: not only is it possible, but if the wish is for the plural Pairs of Seven League Boots, the game will grant the player with several pairs which can be sold, Offered, or kept as spares. This also adds to the possibility of getting boots that give a large bonus to PV or DV in addition to simple haste of movement.
Wishing is not the only way to gain the boots: while there are no stock pairs in the game they can be randomly generated in shops or in vaults; however, in versions 1.1+ of the game, some players may even start of with them. If a player chooses to play a Bard and gets at least three starting talents, he can choose Charming, Boon to the Family, and Heir. Heir allows the character to start with a special magic item- which, for bards, is a pair of Seven League Boots. There is no guarantee that Wished for or Heirloom Seven League Boots will be blessed, so it is strongly advised to bless them with a potion of holy water as quickly as possible.
The one problem with Seven League Boots is the fact that they're just normal leather and neither Eternium nor artifacts: they get burned up in the Tower of Eternal Flames, and can be dissolved by acid and smashed by Ratling Warlords.
Sources:
http://www.gamesreviews.net/archive753-2005-2-229243.html
http://www.andywlms.com/adom/adomgb-toc.html
ADOM manual