Continue a Kitas means you have to leave Indonesia, for example to the Indonesian Embassy in Singapore. A Kitap is a five-year residence permit, thus cost five times the price of a Kitas. A Kitas application currently costs 6 million rupiah, a kitap 30 million. When you apply for a Kitap you can just stay in Indonesia, you don't have to leave the country, and you don't have to go every year one or two times to the immigration office. Seen from a financial point of view, a kitap is too expensive, but you don't have to travel and less hassle.
The Kitap application takes about 4 months and you will need the following documents:
Original passport
Original Kitas
Original Blue Book
Original SKLD, police registration
Domicile letter from the village where you living
Proof of land/home ownership or rental agreement, in Bahasa Indonesian
For rent, copy KTP (identity card) from te landlord
Copy KTP housekeeper
Copies of income, bank statements, retirement letters, etc.
Copy health insurance
Copy liability insurance
Copy death insurance
Map of the area residential address