We paid all of our money to him up front, which we were dubious about at the start as we didn't know him but I wouldn't say that this was a problem at all.
He made sure we were happy and safe and had full bellies at all times and made sure that we knew everything about altitude sickness which we didn't get in the end thanks to his slower pace higher up and aclimatisation walks. We also took Diamox, under his recommendation and we were both fine and only suffered a bit of tingling in our faces (a side effect of the drug)!
I would recommend Sanjib to ANYONE that was thinking about going trekking in Nepal, I would love to go back and visit him and do another trek with him when I have the time! There are so many guides out there that claim to do everything that he does but I wouldn't choose anyone without a recommendation because you hear so many stories about dodgy guides and it would be so sad to lose your money and have a bad experience.
Feel free to email me if you have any questions and enjoy your trek!
www.nepaltreckingguide.jimdo.com almost 6 years ago