Do you have a panic list? (If not, don't panic.)
As mentioned in an old issue of The Writer magazine I was perusing while procrastinating the other day, author Janet Groene says she has a panic list: a list of phone numbers and supplies she keeps handy in case of emergencies.
On the phone list are the numbers of her computer consultant, the support lines for the software she uses, her office supply store, an office machine repair shop, and a temp agency that can send over an assistant at short notice.
Her emergency supplies include packaging and paperwork for overnight mail and FedEx. If something goes wrong when a deadline is looming, she's prepared to handle it.
Every person will have his or her choice of items for a panic list, but it's a great idea to have one with at least two options for each type of person you may need to call upon, and several of each of the key items.
I'd include an extra set of inkjet or toner cartridges, an extra hard drive you can boot up from if your main hard drive crashes, and extra batteries of various kinds.
Optional but helpful: the numbers of at least one friend you can call who respects your writing and can talk you back up when you've had one too many rejections or feel yourself falling prety to the imposter syndrome.