If u r new and interested on FS.. maybe u can do some research by reading forums here or read the research papers which i've found from the net and posted in the forum before. The research paper have documented alot FS info. Try and see FS video posted by Mindstorm n me to understand how the FS fight. The videos posted mostly from good FS fight. You cant get this videos anywhere coz theres no video from the internet on FS fight previously. I bet u can only hear ppl play fighting spiders from mouth of c pics only...
In actual real life.. most of the normal fight lasted very short while only.

At places where FS habitat, theres are alwys more than 1 male and 1 female FS of coz.. If the places have alot of leaves, lotsa insects/food supplies, not too expose to hot sunlight..there will be quite alot of fighting spiders. You just need to try to look for its nest or its habitat place hard enough.
If the area is good place, there will be alot of FS and sometimes if u r lucky, u can see 2 male FS fighting direct in front of you eyes at its habitats.

U know why ppl call them FIGHTING spiders? Its because of its amazing fighting ability skills and FS can fight unlike other spiders.. just know how to kill only.

Frequency the FS fight in wild compare to the captured1?. 
Nowdays less ppl catch fighting spiders to fight and its so difficult to find other people who have good fighting spiders to fight with. Even if got arrange fight also like once a month? Fight with other own caught FSs also like 1-3 days once if only can catch any FS. 
Seldom people fight the spiders continuously coz the FS will be exhauted or injured. 
The ones captures, its fight is normally arrange for similiar other FS which is about the same size or slightly bigger/smaller abit to have a fair fight.
The fight depends on its opponent, if the FS fight is just a short and light one, its possible to have few other rounds of fight.
If the fight is a fierce one and the FS injured, its put back in its case for rest. Feed  with food n drinks for it to recover. Will only let it fight few days later when its active back.  Basically its depend on how the owner take care of FS, the food, its place to live and how the fight is conducted.

In the wild at its habitat, FS have to fight with red ants tat try to invade its nest for dead insects, black ants, other species of spiders, and also its own same species for survival. Hot weather and heavy rain also not good for FS. Its the survival of the fittest. FS will build its nest at a safe place from its predator. Male FS have more risk compare to females FS, male FS alwys roam out of its nest to find food and female FS everyday. The female FS most of the time stay at its nest and wait for insects to passby or wait for strong male FS to mate. If the FS is injured in the wild, chances for it to survive is very little coz hard to move around to find food n water. It also unable to run away fast when predator comes.

When i try to search for FS, I do came across injured FS, 1-2 arms missing, 1-2 legs missing male FS.. small young FS get eaten by ants in its nest.. etcs.. Other species spider like Spider Besi also kill n eat FS..  i also got found some Spider Besi at FS habitats and its kinda scary if its big. This spiders is a killer.. it kills FS as part of its food. FS is different, most of the time for same FS species, they will only fight for territory, female n food. It hardly eat its own species unless if its really hungry.

Not all FS are excellent or fierce fighter. Only some are really fierce and can fight very well. Chance to catch a very big n fierce FS is not easy unless u are really determine to find one... like Mindstorm or me. Most of the FS fight normally just a short 1, just few secs.. coz the weaker FS will retreat n ran ..some even bfr the fight start afer face contact or judge opponnent arms fighting stance. FS able to judge its opponent size and strength base on its arms fighting position and its fierce fighting stance/dance. For the fierce big FS, they will engage the fight direct and will retreat immediately if sense it cant defeat its opponent. A good example here is like BigHead vs BigGuns or Archilles vs BigGuns.

FS will fight most of the time whenever they see each other just like fighting fish. Its just depend on whether to accept the fight n also how long
can they fight. If they see another male FS nearby its area, it will move closer and challenge it to a fight. Its their natural fighting instinct. By fighting also, it will makes FS stronger  for survival and stands a better chance to mate with female FS eventho no proper research available on this belief.
Smaller ones or weaker one of coz will retreat or just fight short time n run away. 

FS is a natural born fighter. They will not lose it, if it lose in a fight, it will become scared but after sometime it will be confident and start fighting again.  Injury from fights whether at its habitat or arranged fight is the about same coz the fighting spiders will decide how it want to fight. If lose, the FS can run away under the leaf or jump away. Its more depends on the FS opponent it fights with.  If fight against a big n fierce FS directly... the FS will be exhausted most of the time but will be able to recover fast if well taken care by its owner. Injury like broken arms, legs teeth and  death do happen if both FS doesn't want to withraw from the fight but very seldom...unless u can find alot of fierce fighting spider to fight n always let them fight all the time. Normal FS fight are just to defeat its opponent only and NOT to kill or injured them badly. The CHOP FS are the one that can coz bad injury or death for FS most of the time if got attack by surprise.   

For me, i feel its harder to find a strong or fierce FS to fight with for those captured one as compared to their fights at the wild against their own same species and also other predators at its habitat. 

If u r not sure about what i've wrote here, u can go and try catch one or few FS n also try to look for people who have FS for arranged fight.
Try and see how many of ur FS and ur opponent FS are really good fighter that can really fight well.
Then maybe u can know better whether the chances for the FS to get injured in the wild or arranged fight is more or less.
v_viper88