I traveled for quiet a while, including 3 years straight in developping countries and used my water filter almost every single day. I would certainly not recommend to do what the locals do. It can be ok in western countries, definitely not in poor countries. Indian drink water from the Gange River, for example, I would not recommend to do the same. I used my filter mostly for financial reason (and secondly because I traveled in remote areas like Tibet), even if bottle water are cheap, it ads up. Of course if you travel for a few weeks and if you are not planning to bike in remote areas where bottled water are not available, go for buying bottled water and forget about a filter (you can bring tablets for emergency). But if budget is an issue, and/or if you plan to bike in remote area, I would recommend a filter. Tablet sucks, it's ok for an emergency but that's it. I used a pump filter for 3 years (the First need from General Ecology) and then I switch to the MSR miox purifier. The latest is FANTASTIC. If you use it correctly water doesn't taste any different, in a few minutes you can purify liters of water, it's as big as a big permanent marker. Cons: use batteries and salt (very little though), and you need clear water (but with a pump I would not recommend to use muddy water as it clogs the filter very quiclky - maybe it's better on the Katadyn model since you can scrub the filter to clean it, Im not sure). the First Need Pump filter is good. Pros: no batteries, you "can" use unclear water, no bad taste; cons: heavier, need to pump, filter get clogged after a while and it becomes a work out to pump (not after 1 month though). There is also the Steripen which use a different purification sytem (UV I believe - the miox create a chlorine/saline soltion that kills germs, just like a miniature city water system purification). But otherwise the idea and pros and cons are about the same. Enjoy your journey.