28 now, have already started investing in US equity. Just wondering if there is a need for SG stocks as well? How is the allocation between US stocks and SG stocks?

Started recently with SG blue chip companies, then moved to US stocks as there are more growth in US stocks as compared to SG stocks. SG stocks are more of dividend-based rather than growth. Make use of our age to gain more capital before investing more into dividend-based stocks for passive income...

I have 15% in SG and 35% in US. I like to keep a small portion in SG for the stable (albeit not growing) and relatively high dividend yields, as well as to gain some income in SGD as a currency hedge. I consider my SG stocks like bonds - reliable, steady, stable income, and not the growth part of my portfolio.

No SG stocks at all. Limited growth potential and poor management of local companies like sph / Singtel etc

Singapore stocks historically have lower volatility, meaning less risk but less reward. Since you're still quite young, if you know your stuff you might want to go US straight and just ride out any volatility and down swings. You have the time.