We have ours last 8 nights with no odor.  The length of time depends on the outside temperature.  The chemical you use is of extreme importance since the toilet recirculates.   We only use the Thetford Aqua KEM.  Their Aqua GREEN is not for recirculating toilets.  Same for products similar to Aqua GREEN.  We have developed a routine of only adding 2 quarts of water, 1/2 of an 8 oz. Bottle and 1 more quart.  We only allow liquids in the toilet.  No paper, etc.  When the toilet is full enough for the pump to recirculate, we add the other 1/2 of the bottle.  This way we can go 8 days without it being full.  On 2 or 3 night trips, we never have to add the other 1/2 of the bottle of chemicals, unless the weather is real hot.  We have logged over 120 nights in our TrailManor in the past 3 years.