In general, at hotels, lodges, restaurants, etc., a 10% tip is the norm. This assumes that you received service that you consider to be good/friendly/pleasant. If you did not receive good service, then there is no point in tipping. If you received service that you consider goes beyond that which you would normally expect, then you should tip accordingly. A waiter or porter normally earns between $4 and $8 per day, depending upon the establishment (small café or big hotel), so tips in excess of a day’s wage are exceptional, unless they are being shared.
On safaris, it is common practice to tip drivers, guides, porters and other staff if service has been good. Some recommendations for tipping:
Driver/guides: $10 per client per day
Camps and lodges: $5 per client per night
Gorilla trekking guides: $15 per client per trek
Gorilla trekking porters: $15 per client per trek
National park naturalists: $10 per client per walk
It is difficult for locals who receive tips in small denominations of US currency to convert to the local currency. It is best to change money into the local currency and obtain small bills. Tipping with the local currency provides the recipients with the most value from your tips. Please do not tip in US$ coins as they cannot be exchanged.