Although I agree it’s not expected, it’s always appreciated. I usually tip housekeepers every few days and the doormen on leaving, especially where service has been good. I also tip if I’m leaving a bag in long term storage. If during a month stay I’ve spent $50-100 in tips to housekeeping, I’m not too concerned versus the overall cost, probably less than 1%. One thing markedly different from most other developed countries is that tips are genuinely appreciated and often result in little notes of thanks ... I’ve even had small gifts in return sometimes, or extra chocolates etc (try tipping a taxi Uncle and you’ll have made his year, or take your own tray to the collection area in a hawker after eating ... it’s nice to be nice). People are very proud to be recognised for good service, and I’ve no doubt many in the service industries in Singapore are looked down on, yet work extremely hard. There’s the old adage that it’s not clean, it’s cleaned! Keep in mind that Singapore wages in the service sector are often shockingly low given the cost of living, with many elderly staff, and the service sector as a whole is unremarkable - it’s the exception to the norm to find good service, certainly compared to places like Thailand and Indonesia. On the occasion I find good service, I therefore don’t mind showing my appreciation, whether it be in Singapore or elsewhere.