It's depends on your scale problem. But I guess you mean perfromance (and not maintability or other) problem. There are a lot technics on different levels to sa

It's depends on your scale problem. But I guess you mean perfromance (and not maintability or other) problem. There are a lot technics on different levels to save you for some time depending on your bottlenecks. Without concrete details of your stack nobody can give you "the answer". But in (my) practice, small improvements on right places can speed up your site up to 80%. Depending on your client presentation, you can hide some latency by minimizing and merging css and js-stuff and put them to cdn and cache forever. Decide to master-slave your database, cache query results and so on. These relatively small changes give you some time to develop more deeply changes.