I installed my first mini split just over 3 1/3 years ago. We have 3 Gree 9,000 BTU 27 SEER Terra Ductless Heat Pump in out bedrooms. I have a two head LG in the living room and the kitchen.
We have not run our gas heat or central AC since I have installed all my mini splits.
At one point in this review (
http://ecorenovator.org/forum/33746-post117.html ) I said I really did not need the manifold gauge set.
I first bought a cheap set off ebay that was junk. Then I bought Yellow Jacket set that I really like. I have used the manifold gauge set a couple times since I installed my mini splits.
I think it was worth getting them and I am glad I have them.
(Jeff had correctly pointed out that I would be glad I had them later and he was right)
I bought a 25 pound Freon 410 and it is very nice having that handy.