You need access to a chrono to make sure your load makes power factor, but once you get it set, you don't really need it until you change lots of powder. If you can borrow a friend's chrono for a week or two to work up a load, you can put off buying one. That's what I did, but now I'm going to start working on loading for 223, so I'm going to buy one.
Having your own timer for practice is essential IMO. Steve Anderson's book Refinement and Repetition plus a timer with a part time feature is probably the best practice tool investment you can make.