How fast do you turn in translations?
There's no single answer. This all depends on each project, i.e. from their maintainers: it's up to them to request the exports from translatewiki.net and then import them into their development repository, test them, patch them if needed, submit corrections back to here to fix some locales or typos, or problems reported by translators; then when this looks OK for them, deploy their development version to a release of their application.
Each project may have information on their project page here in translatewiki.net detailing how often they update their application into their development repository, but the release of apps containing them may still be delayed. So look at thje version of each application (or webapp/website/wiki) you are using, and ask to their local administrators to ask them when they will release them.
Translatewiki.net only wants that translations made here are imported into an accessible development repository so that users can also test their translations in a test environment even if it's still not released (but the application should release in a few months, or ther contact maintainers must reply to support questions and inform translators about what is going on (they should clearly state, when they are requested, that they really continue to develop their app and will support new translations).
Otherwise, without any answer, the translation project hosted here may be stopped by a decision made by TWN admins (and TWN users will be informed); a suspected project may also be resumed if a stalled project has been forked and taken by someone else that wants to support it and update it.
Translations for MediaWiki core messages and for MediaWiki extensions supported by Wikimedia usually take no more than one week to be imported, tested and deployed (but there could also be delays, notably when messages are updated for a newer version of some extension which is still in beta: the deployment will not go live in standard wikis, but only in specific test wikis: you have to look for information in Wikimedia Phabricator to see the deployment plan, or you can read their "Technical newsletter" in MetaWiki for those new messages modified or added in English; however simple translations of messages that were already released in English can be deployed much faster, so remember that there are different stages for deploying them, including within the same project or the same extension, depending on the application or extension version).