The longest period without actually developing AIDS is 10-15 years. 8-10 years is the most usual period length.
Mucocutaneous infection is a term that describes infection which affects either the skin or the mucosa. Unexplainable and often sores or small skin wounds might be a sign of decreased immune system which is actually affected by AIDS.
The very first symptoms of HIV infection occur very soon after the infection, but are often unrecognized since they are very similar to those of other infections and are not specific only for AIDS. Once the immune system is decreased enough, the symptoms of AIDS start to appear. Meanwhile (between the very first non-specific symptoms and the AIDS symptoms) no other symptoms appear which lets the infected person to spread the infection without even knowing that he/she is already infected.