I wouldn't say there is a certain time that you should buy XRP, instead I would say that it's a buy under 5 usd. I think the same is true for NEAR and LINK too. You can wait around hoping that you catch a good deal or invest in something else that produces dividends that you can in turn, reinvest in other crypto projects. That's what I plan to do on MAXX dot finance, I'll stake my MAXX and use the staking rewards to invest in Silver coins but you could do something similar by reinvesting in more MAXX to stake for more APY or use your staking rewards to DCA into XRP over time.