I had hep vaccines as a child, I'm 28 and want to travel more, will I need new shots? Will it last another 20 yrs? Should I get a + b, anything else?

Find new information. If you will go to the current cdc website listings you can review current needs for anywhere in the world. See:wwwnc.Cdc.Gov/travel/.
Hepatitis vax. Hepatitis a vaccine protection is thought to last up to 10 years before a booster series is given. Hepatitis b vaccine is thought to confer protection up to 25 years, but possibly lifelong. If you don't wish to undergo another series of vaccinations, you can ask your primary care provider to ask for antibody titers in blood; this way, you'll know if you have immunity at present; safe travels!