Recently bought a Navy 24 hour bag...I was under the impression it would be a buy it for life product like the 256/257...but now I see it's actually made of thinner less durable tin cloth vs Twill. :-( How long can I expect this to last? Do I need to baby it since it's not the thicker material? I usually try to fit my laptop, and several heavy books into it. Will the fabric be able to support this?