Re: If Combat Is Not The Main Focus
If a combat has permanent outcomes, that is a major part of the game, whether it's frequent or not. So I'd make sure you understand focus and importance are both most relevant to a game's design. A big desicion or event, even if rare, is nonetheless a major event. I've never been ina car accident. I've had my home be casualty to fire. It was one month of trauma out of nearly 500 months of my life. Still, it was something I had agency in, and something if I were character in a game, would want to extrapolate every option I had, to mitigate the loss of my possessions and comfort of my daily life.
An example would be if you ran a slice of life game, and a note of the game is that there is a criminal gang in the city. Most of the time, the PCs would be shopping for groceries, avoiding getting traffic tickets, dating (and more...) working at their job, and paying bills; maybe getting nice furniture, pets, or electronics. Then when gang member mugs a PC, it may be the only point in the game a PC could die. You, as GM, should decide, "how likely is that?". If it's zero, such as the gang member will stab the PC if they resist, but it'll take half and hour to bleed out, and another PC can get an ambulance, or get them to the ER, then that's fine too. In this case though, the gang member probably took their ID, their credit card, their cell phone, and their cash. The PC might also have a a medical bill too. Then you have to ask yourself, "Is this going to be fun for me? What about the player?" If no, ask "Is this a good way to punish failure, and show actions have consequence, as to make the game feel more real?" If no, then you shouldn't be introducing the combat at all. It's not fun for anyone, and doesn't lend to ground the characters, it's distraction. Character sleep and eat, and do other things that are vital; but no time is spent on them. You can say the gang is in the area, but just assume it's background, like the architecture of the city. The gang isn't a character in the narrative sense, but a quality of the city, that is more a character than the gang itself.
Flow charts and statistics help with this decision to roll. If any flowchart has catastrophe, and only your group can decide (they may not agree though!) what that looks like, then you should kill that whole channel of the flowchart and not roll.
In war games, I like the minutia of combat. Unlike evileeyore, I woulld be extremely dissatisfied in settled mech warrior, mage knight, or Warlords: SotS battle with a mere rock paper scissors, or a roll of 1d20, highest wins. If ever I had the chance, even in very scarce cases, to settle a war game with a robust system; I would.
As GM, if I don't want to roll out a combat, I just default to the players winning, or avoiding combat. Just this week I GMed, and earlier the group had the chance to kill some people (they are infernals on the Blessed Isle--stuck over enemy lines) and I just said "You all avoid this, I assume. If not, you'll easily kill the group of men, but leave body count for later" they opted to kill some the first time, and we rolled it out. The third time they understood the consequences, and chose to avoid combat. In the second case, they killed without a roll, not even one. The first gave me benchmark, and I used that to determine they'd not need to use any magic to have good chance of success, but if they did, they'd certainly win with no reasonable chance injury they couldn't recuperate in a few hours. They did, however have a body count that was piling up, to implicate serious threats, thus they chose to try to let the heat die down, and so avoided the local police.
That was in a combat heavy game. If I don't want to roll it out with the system, I don't at all. I just settle actions but declarative statement and reasonable outcome. If it's major, I want the multitude of factors that govern combat, to come into play. It is a combat heavy game, even if it's only 35% of the session play time. Combat has a likely outcome of death. In the region, combat would lead to death for the characters. It is out of character for the canon area not to kill the characters, except in rare cases. Death is also not the end for a character. A major setback, but not game over.