We normally can go a full week without dumping, but for those situations where it doesn't work out, we carry a small 6-gallon Tote-n-Stor and a 7-gallon repurposed water jug. The Tote-n-Stor is normally used for black and/or grey waste, and the ex-water jug only for grey waste. One or two "dump runs" is usually enough to get us to our destination date. The two containers easily fit in one storage bin along with our waste hoses and fittings. If it was more of a problem for us, we would have a larger capacity tank of course, but this setup has worked well for us so far with minimal inconvenience.