I've been using the same black pleather rucksack from ASOS for probably the last 6 months now and have found it really easy to carry, plus it was more than plenty big enough to hold everything I carry on a daily basis. Here's a picture of it.
It wasn't too expensive, I think I paid £18 or so for it earlier in the year. I liked the rose gold hardware, i.e. zips, buckles, etc., but the long top zip that opened the bag had always been a bit temperamental, as the teeth of the zip sometimes moved and it wouldn't zip up or open up easily on occasion.
Anyway, I persevered with it, until the other week when one of the teeth fell out, leaving a gap in the zip, so that it just wouldn't work anymore. I was a bit disappointed, as I haven't really had the bag that long.
I proceeded to cut the zip out, with the intention of trying to replace it and carry on using the bag, and then it got set aside for a while and I used a different bag for a month.
On Friday night, I decided to try to sew the new zip in. It doesn't fit exactly, and doesn't match the zips on the front of the bag, but I figured it would do for everyday use, going to the gym, etc. I hand stitched the zip in place, as central as I could and then stitched up the ends where the zip didn't quite reach to. I was pretty happy with the results and my bag is now back in action.
Here's what it looks like now. I t doesn't look too obvious and it has prolonged the life of the bag. In addition, I now don't have to negotiate an annoying zip every time I use it.
I much prefer this bag to the one I was temporarily using, as it has more small pockets to house the various bits and pieces I carry around on a daily basis, instead of them all swimming around in the bottom of my bag. It is also more secure, for use in a big city.
I'm not sure how much longer I will use it for, but at least when I do decide to stop using it, I can donate it to the Give and Take for someone else to potentially use, instead of having to put it in landfill and the repairs cost me nothing as I already had the zip in my stash.