I heard about the net pot years ago. I tried it... sort of... without a real neti pot, I decided it was too much hassle. I also live in Japan and I don't know where I can get one. I didn't really want to buy it on the internet and then get ten years of neti pot advertisments in my browsers.
Over the intervening years, I managed to get a sinusitis infection that, true to the doctor's word, reoccurs easily. I have had it flare up about three or four times now. My last flare up made me fed up and I re investigated the neti pot. It was then that I had the inspiration to use a syringe (I use them to teach science and with my son in his projects... they are absolutely great for mini-hydraulics). So I experimented with not pouring saline solution into my sinuses. I injected it.
Once I started using it, I fell in love. I started twice a day as I had the sinusitis. I was careful to research that there are no severe downsides as long as you keep everything clean and use clean freshly boiled water.
I had a few problems at first. Too hot. Too cold. Too much salt. Not enough salt. Too much baking soda. Finally, I figured out how much salt to use (and baking soda... that really mellows it out) and got the correct temperature.
I find that I have more energy now. It lasts throughout the day and Sundays I am no longer begging for a nap, although they still feel really nice. I also swear my sense of smell is sharper. I can really sense my sinuses now, fresh and clear for most of the day ( now I do it usually once a day in the morning).
Needless to say I feel happier as a result of the energy boost. It takes about five minutes out of my day to perform the ritual. Not bad for the payoff. I feel cleaner too.