This is exciting!

Really, it is.

   Last year after a failed attempt at tubeless conversion I decided to try Stan's sealant in my tubes.  I just found the selection of tubeless tires to be lacking any practical choices.  The ones out there are made for competition, in which I proudly do not participate, and were damned expensive.  Besides that, I would still have to carry a tube in case I was in SW Buttheadistan and had a puncture too large for the sealant to conquer, and my imaginary sag wagon was busy at the donut shop.  Anyway, tubeless doesn't make a lot of sense to the commuter and tourist market.
    Using Stan's sealant in the tubes worked out quite well last year.  I had a total of eight punctures that I know of, a number of suspected slow leaks and zero flats to change.   The most I had to do was remove a little wire or tiny piece of glass from the tread, add air and ride.  Easy Peasy. 
    This year I had a lot of tires to replace so I did a little research.  As good as Stan's product is, it has to be refreshed from time to time.  It will harden and congeal in the tube if you  don't.  I found another product called Flat Attack which is supposed to have a useful life of 6 years.  I bought some of their pre-filled tubes to use when I replace a tire.   I have replaced the tires on all my bikes now that it's August and am just as happy as I was with Stan's but look forward to leaving them alone until I change tires again.  I expect to add a new tube with each new tire in the future because the old tube will probably be glued to the old tire by the sealant, but hell I bought new tubes for new tires anyway.  These are a buck or two more expensive than normal tubes but if I don't need to replace them 8 times a year it's a net savings.  The sealant is also supposed to be environmentally friendly.  I feel all warm and fuzzy using it. 
    There is a bit of a learning curve to all this.  The one possible drawback is that you can get the sealant into the valve.  All you have to do to prevent it, is set the valve at 8 or 4 o'clock position (using your wheel as a clock face of course) so there is no sealant trapped in the stem or a pool of sealant underneath when you are filling it.  That's so simple even I get it. 

Lookee there!  Perfect form already, eight o'clock on the nose and no flats in nearly two years.   No, I don't know what the sealant weighs.