Apple’s latest smartphone has brought with it the need to adopt a new SIM standard across every carrier that supports the device. So far the new nano-SIM is only being used in the iPhone 5, so if you are getting one you’ll need to either get a new SIM from your carrier or trim your SIM to fit the new device. The nano-SIM standard uses all of the same electronics as the previous SIM versions, but the plastic border that holds all of that tech in place is much thinner, to the point of being practically non-existent. So, do you grab a new SIM from your carrier, or take your chances trimming your existing SIM to fit?Trimming your SIM can be a tricky process when trying to get that card down to the right size. If you nick any of the copper panels, you risk the SIM not working at all and wasting your time. There are a few companies out there that have made SIM punches — where you just put your card in and push down to pop out the right sized card. While a great way to get the SIM down to the right shape, most of these stamps start at about $25. Since the new SIMs are free at any carrier, unless you are going to make it a habit to punch out every SIM you see it’s probably not worth it to you. Most people will attack this situation with a pair of scissors or a razor blade, and with this it’s the steadiest hand that will win.Unfortunately, there’s more to the nano-SIM than just trimming the plastic to fit. The nano-SIM is also thinner than a regular SIM card. If you try to fit a trimmed SIM into the tray on the iPhone 5, you’ll notice it’s a bit of a squeeze. In fact, you could risk warping the SIM tray or scraping the copper on the SIM itself by trying to cram it in there. It’s not a huge difference, going from 0.76mm to 0.67mm, but that 15% is enough to cause problems. The least damaging way to shave off that little bit of extra plastic seems to be to rub the back of the SIM against a piece of fine sandpaper . If you rub the card evenly against the sandpaper for a few seconds it should shave off what you need for the SIM to fit neatly in the slot.In the end, trimming your SIM is a lot more work than it has been in the past for previous device, but it’s still doable. Considering the precision and sanding needed in order to do it right, and the expense of a SIM stamp, I wouldn’t say that it is worth it unless you are reaching for the “because I can” achievement for the day. SIM cards are designed to be disposable, especially today with carriers continuously upgrading their networks and adding new technologies. Your SIM card from the last phone you bought could either contain some super secret goodies for a faster network connection, or it could slow your iPhone 5 down if not provisioned correctly.