INSTRUCTIONS
Included. You cut the sole to the desired size.
DURABILITY
The instructions suggest changing every 6 months.
I believe this depends on the duration of use and walking style.
OTHER
I use them on top of the old sole and it hasn't bothered me.
The shoes I use are athletic. It would be uncomfortable to put it on top of the old sole in a shoe with a narrow fit.
IMPRESSION
It helped me and they are worth their money.

Both expensive and useless product.
It does not have a good shape that fits well in shoes, it sticks to the foot and comes out when you take off your shoes.
Additionally, the silicone gets dirty (things stick to it) and they are not easily removed.
With less than half the price, there are much better insoles!
NOT RECOMMENDED!

For me, it is not only an ergonomic product. I put them in my sports shoes for extra protection and I had pain in my feet, especially in the heel area. I tested one shoe with the insole and the other without it to make sure that they are indeed problematic.

Very good insoles with a lifespan of about 6 months (depending on usage). Those of you who mention that they stick to your socks and come off with your foot, most likely you are placing them upside down! The colored gel should be on the bottom and the fabric lining should be facing upwards! :)

I bought them for the Nike Air Force because of the very hard sole despite the air chambers....
From small to insignificant improvement........
Advice (also for myself.....): We should spend a little more money for a pair of good shoes, rather than later spending money on ineffective insoles.

I have them for several months now and recently they have somewhat lost their "shine" as they say! Overall, they are perfect because I mainly wear them with Nike Air Force shoes which are leather and hard shoes, and they don't bother me at all in walking and posture despite my foot issue! They are worth it for everyday use because the gel they have makes walking lighter, but after 8 months or a year they need to be replaced (depending on their usage, of course)

They are very difficult to adjust to the shoe and also because they "stick" to the sock, every time I take off my shoes, the insoles come out. As for their performance, I can say it is average to poor. Maybe it's worth putting them in shoes that you wear for a long time and the sole has become one with the ground, or alternatively in shoes with a very hard sole that are not meant for long walks