I like to do alot of go problems in my spare time. Now i was wondering how long should i take on a tsumego for the best improvement?
I tend to take as long as needed for any problem (up to 5/6 minutes) and that allows me to do problems that are above my level.
But a 2 dan friend of mine suggested that its better to do a lot of easier (not too easy ofcourse) in short amounts of time.
What do you think?
1 minute max but 10 seconds and under is to easy
What is wrong with testing different regimes and tracking your improvement?
I for one think that variety is a spice of life. Do what suits you, but I am not sure you will progress much by doing only “easy” tsumegos quickly.
Unless you tackle harder problems you will grow slowly. So what it took 6 to seven minutes. You solved it and next time it will be faster.
Do a bit of both and your dilemma should be solved 
you wouldn’t wanna play only the one opponent you know you can beat, right?
I started solving tsumego last week because I noticed any time an opponent would invade my territory close to the corners or sides I couldn’t kill him. He would just unfairly live (well, I say unfair, but I understand it’s my fault if I’m bad at it, not my opponent’s).
I bought the Tsumego Pro app in Android for that. When I started I couldn’t even solve the easiest ones without failing lots of times before getting it right. Less than a week later and hundreds of problems solved I’m now finding it easy to solve even some intermediate ones in a few seconds in the first attempt. The easy ones I usually solve in 10 to 20 seconds in the first attempt, BUT there are still some of them that keep me thinking for many minutes. My reading has definitely improved though, as well as my “skill” to detect and force dead shapes, counting liberties for groups many moves ahead, apply tesujis and other tricks, …
I’m not solving hard problems yet (I tried, but the time it was taking me to solve them - usually by bruteforce - wasn’t paying off, so I thought maybe I should get the basics right before moving to more advanced problems).
Yes, it’s a great app. (free with many problems - you can buy additionals) I have it on my phone as well and run it every day (mostly for the daily challenges)
However I feel compelled to say this: It’s a great app and improved my game surely by a lot. However to gain even more one should carefully (and criticaly) study the result. The main problem is that the app offers very suboptimal play for white (without any comments), which might sometimes mislead novice players that it is a great tesuji to capture 12 stones, while in reality white would (for example) just sacrifice one stone and let black live with a few points.
I am also convinced that a (very) small number of tsumegos presented is actually wrong or up to discussion (living with 2 points vs. advantageous ko with much more etc.)
So, don’t get me wrong great app and great help. Just do not take it as a bible.
And to be complete (although I am sure you already know these)
www.goproblems.com offer a huge library of usually commented tsumegos
and http://gochild2009.appspot.com/ offers many tsumegos sorted in packs to teach different ideas and approaches (which I think is a great idea, however the execution of the website is terribly anoying. For me at least) - it is also aimed at novice players.
You are right. My friend who is 20-ish kyu was also using the app, and he kept asking me why white would sacrifice A+B stones when it could sacrifice just A… you must keep in mind the app is trying to prove that no matter what white does, you escape with whatever stones you are trying to. The app is not really playing what white should to minimize its loss. If you are not critical enough you might end up acquiring bad habits. I’ve reported one problem which had an wrong answer marked as correct, and a few with correct optimal answers marked as wrong.
I will check these websites.
One more link IMO worth sharing: https://www.101weiqi.com/ (it’s in Chinese so you may need to use google translate or some other tool to help you navigate).
There are 8 new tsumegos to solve every day and access to few thousands historical ones.
Note: The easiest tsumego is usually marked as 9 or 10k, but they are actually much easier to solve.