Plugins in two places?

The CMS Questions
1

I’m working on a site. We’ve brought in a developer to set up the e-commerce. He has put plugins in a folder called ‘vendor’.

I now want to use a new plugin and the instructions are to download it and put it in a folder called ‘plugins’ in the ‘site’ folder.

Does it matter if plugins are in two places?

2

Plugins that are Vendor folder have been install using composer. You can also add manually installed plugins into the plugins folder. If the plugin you want to use has instrunctions for installing with Composer I would stick with that installation method as it makes keep plugins updated easier.