Tolerance to not-so-perfect squares

[Aleburzyn]

Hi people!, all of us have read in this forum about the importance of getting perfect squares of paper. I put a lot of effort trying to get a perfect square, my methods are the usual folding the diagonal and cutting A3/A4 sheets or draw a square with a wood template and then cut. However, at least in my case, most of the times when I make the first creases of the model I realize that the borders aren't so equal as expected, I'm talking about very small differences, about 0.5/1 mm for a 20cm square (A4 case).
What do you do in these situations (if they happen to you)?
Usually, I get very irritated when that happens, to the point of start cutting another square (and yes, the same happens again and again). But, in the last months I decided to continue folding instead, and some of them went right.

[Jonnycakes]

I generally curse for a bit and then continue folding If you use non-commercial paper (as in large sheets with rough edges that you must cut yourself), you have more control in how accurate your starting square is. It is reasonable to expect a better square than machine-cut papers would give you using this method (but it makes it all the more aggravating when you only have yourself to blame for the inaccuracies).

[Ondrej.Cibulka]

Many models have big tolerance in square precision. If you have "square" which is actually not square, do not hasitate and fold it. You will see how manipulate with such paper with some practise.

[bethnor]

What do you do in these situations (if they happen to you)?

probably most ppl continue, as most commercial kami is not cut to a perfect square. all that being said, a lot depends on the size of the paper and the complexity of the model. if you have a large sheet and a very complex model, you have more leeway re: inaccuracies of your starting square. if you have a small sheet and a very complex model, you have less leeway.

[Finward]

Perhaps is part of my low hability, but I don't care a lot in how exact my square is (as long its not an obvious rhombus). However, the same thickness of the paper will bring you accurancy problems.

[Brimstone]

When you are folding animals it si easy to correct in the end by a small crimp or something to disguise one longer leg than another, but when you fold geometrical models, accuracy is very important and so far I haven't been able to find a workaround for imperfect squares.