My friend mentioned to me that it is possible to get a multiple entry permit that lasts the entire life of my Taiwanese passport(臨人字入出國許可). They said it is possible because I have a US passport(which allows 90 day visa free).
They sent me this link which is a bit over my chinese level:
immigration.gov.tw/immigr-la … 8873570804
無戶籍國民有下列情形之一者，經駐外館處書面建議，入出國及移民署得發給與護照效期相同之臨人字號入國許可：
一、 參加僑社工作對僑務有貢獻。
二、 依華僑回國投資條例申請投資經核准。
三、 駐外館處或國際機構人員。
四、 具我國已賦予免簽證待遇國家之永久居住權。
I contacted TECO and I got 2 different responses. One suggesting that I am only able to get a 1 yr multiple entry permit and the other suggesting that this may need to be done in Taiwan. So I am quite confused. Does anyone have any experience with this?