Are There Rules For Opening Covers That Are Then Going To Be Collected?

Sometimes I get nice covers sent to me that I decide I want to collect.

However, I've been opening all of my covers with a pair of scissors across the edge. This method is very easy, looks clean (in my opinion), however, it does slightly shorten the length of the cover.

Should I be opening covers a different way?
Every time I try to open them from the flaps on the back that have been adhered, I feel like I'm massacring the cover. But, maybe this is the correct way.

Thank you!

That's how I save mine,
I use a scalpel, and slit the edge, the opposite side to the stamp/s.
My regime for the past 10 years.

I would not be bending, folding or creasing.

That is why the letter opener was invented.

Is this now considered a reduced cover?

Yes, slightly reduced.
Use a letter opener.

Modern covers can be attractive, but I can't "get around" the self-adhesive aspect, i.e. stamps, sealing flaps and labels (air, registration, etc.).

If it were just the adhesive tape that many people are compulsive about using, I could deal with that, but the others are a little too much for me.

Slit carefully along the main flap. No paper removed.

'
I prefer to not open along the upper edge because it creates a fuzzy edge near the stamps, postal markings, etc.

I prefer to not open along the lower edge because I plan to introduce stiffeners / separators to keep the face safe from the gummy areas on the back.

So I mostly use an excellent pair of scissors (Fiskars) to take one millimeter off of the left edge, as you do.

Sometimes, when I'm in That Mood, I'll use the scissors to open the lower 1/2" of the left edge, and then insert a knife, and work my way north.

Cheers,

/s/ ikeyPikey