Does reputation increase/decrease only by completing quests or is there a way to gain it in other ways (random encounters maybe)? I noticed that Fallout does not credit my character for positive actions if I did not talk to someone before to give me the quest to do them (SPOILER: I killed Decker by myself without talking to the police guy and I did not get the reputation increase (even though he does acknowledge that Decker is dead). Had I talked to him before, he would have helped me kill Decker and I would have gotten a reputation increase). I'm just wondering whether I should care for lost reputation in situations like this or not and if I will be able to increase my reputation later when/if I need it. In other words - is reputation pool unlimited? For example, XP points are unlimited because of random encounters. Can the same be said about reputation?

Please do not post spoilers when answering (or at least mark them as such). Thank you.

Rep/karma in fo1 is really limited. It's mostly quests but killing some characters can effect it.