Over at The Den of the Lizard King, another great post about Traveller. This one tackling skills:
The first thing to remember is that Traveller characters are competent. Skill-1 is employable – you are good enough with it to get a paying job using this skill. Skill-3 is a professional – typically enough to get you a license in one of the Professions, such as being a Medical Doctor or a licensed Engineer. In ordinary situations, they do their jobs competently.
Under CT rules, for example, First Aid and even Surgery for Severe Wounds do not require a roll – you got the paramedic (First Aid) or the surgeon (Surgery), you get results. They only need to roll dice when there is a significant chance of failure even for a professional, and when failure will have dire consequences. For example, if a doctor character would try to perform the above-mentioned surgery in some colonial hellhole when only the local TL-3 tools are available, and not in the default TL8+ Medlab.