It depends on so many different variables, there's no cut-n-dry answer. The sooner you use them, the better & the longer in storage the more gentle you'll have to be waking them back up. If you're really after long term storage, slants are a good way to go, but all in all it'd have to be a very, very special strain to be even close to worth the hassle, even if it's not commercially available. Even then I'd be more likely to brew a 1 gallon batch after a month or two of storage & repeat as necessary.
Rinsing is a great option to get more batches out of your pitch & clean ferments, but it's not meant to be a long term storage solution. It'll work for a while, but it's not always as simple as taking a sample out of the fridge, throwing it in a starter for a few days & pitching it. It's fine if that's what you're looking for, but if that's the case you can save yourself a lot of time by just buying a new vial. When I was doing some really heavy yeast work it was 20-30 hours per week for months on end & I was doing it because it was fun, not to mention the ton of stuff I learned by doing it. Personally I think that's key in the whole process; if you're just looking to save a couple bucks, it's probably not the right road to go down.