I spent less than $6k in Australian dollars for a 4.5 month trip in Asia. This figure includes flights, visas, vaccinations, travel insurance, local transport, food, accommodation, activities, whatever you can think of.
The answer to your question would depend on which countries you want to visit and how long you want to stay in each of them, your travel style, your requirements in terms of comfort, what sort of activities you like to do, how flexible you are, whether you can score cheap flights, etc.