varchar or text

Hello
I had a look in previous posts in the forum but could not find the
answer I was looking for.
My question is should I switch from varchar to text.
We have "discovered" although it seems to be SQL that adding something
like 'text               ' to a varchar(50) just silently cut the text
while a text with check(length) - or also a varchar with a check raised
an error.
I was suggested to replace varchar(255) with text when we have no idea
on the default length we would define or if we do not want a threshold.
In that case I was thinking about being homogeneous and using text
everywhere adding check where necessary.
I would remove the space strange behavior and would be homogeneous.
I also read the perfs are identical with text and varchar.

My main concern is that if I don't set any check to a text field, it can
be 1Gb large which is a bit tto big to me. Anyway I can't imagine
updating my whole database replacing varchar(255) with text + checks
everywhere. That would make my schema less readable with many checks
where today with \d my display is compact.
I don't know what would be the best ? Keep varchar and live with the
space behavior. Move to text and add checks but the 1Gb limit scares me
a bit.

Thanks for advice or help.