Index card sleeves

I'm going to order some of these on ULINE.COM, and I have 3x5 index cards I use.
I'm debating if I should get the 3x5 sleeves or the 4x6, reasoning is I don't want to get the 3x5 sleeves and be just too tight so the cards won't fit in, anyone thing they will fit perfecftly or should I got with the 4x6's?

I would get the 4x6 for two reasons. One, the 3x5 will fit easy, making them easy to take out and put back in. Two, you may end up needing bigger cards later.

The 3x5's should fit just fine, but you may want to think about it before ordering them. I started with 4x6's and decided they filled up to fast, now I'm using 5x8's and I like them a lot better.

I just ordered a pack of 4x6's, thanks for the info I never thought about a 3x5 getting too full from multiple cards in it.