Today I looked at the map we did 6 months ago during our Kyiv Mapping Parties. Looked and a bit disappointed, because many roads, buildings, POIs tagged with mistakes.

Mapping this area was our first investigation of OSM, so we made a lot of errors. The sad thing is nobody of us reviewed that and check the mistakes. Personally I did not do that, because main part of it prepared one of best Kyiv's mappers - Vladimir Agafonkin (Mourner). I just did not expect there are mistakes. However, this was his first task too. Everybody does the mistakes, especially in beginning.

Learning this I backed to my first good map - residential district Poznyaky (Kyiv), and found that parts which I did first are not as good as later parts: many houses where ugly, not orthogonalized, streets tagged wrongly and so on. Kudos to JOSM: it can make buildings rectangular, find warnings in your map and do a lot of job for you.

So two conclusions from my story are:
1) Everybody makes mistakes
2) Look back and check