Polling an SFTP server to list files in a directory

Question

When is it better to instantiate the sftp client globally vs inside a function as shown below? What considerations favor one method over the other?

For a long running service that polls indefinitely, would it better to instantiate globally so I don't need to instantiate a new client on each run?

Also, is there any difference between using Bluebird's Promise.delay(10000) as opposed to wrapping setTimeout like so:

const timeout = async (ms) => new Promise(resolve => setTimeout(resolve, ms));

Finally, my polling function sleeps at the beginning of the function instead of at the end so my finally block frees up the sftp connection without having to wait 10000ms. Seems okay with the current recursive setup but I'm curious if there are "better" ways to write a recurring task.

Instantiate globally

const Client = require('ssh2-sftp-client');
const Promise = require('bluebird');

const sftp = new Client();

const listFiles = async (directory) => sftp.list(`/${directory}`);

const pollSftpServer = async () => {
  try {
    await Promise.delay(10000);
    await sftp.connect({
      host: '127.0.0.1',
      port: '2222',
      username: 'foo',
      password: 'pass',
    });
    const files = await listFiles('upload');
    console.log(files);
    return pollSftpServer();
  } catch (e) {
    console.error('caught error', e);
    return pollSftpServer();
  } finally {
    sftp.end();
  }
};

(() => {
  pollSftpServer();
})();

Instantiating inside a function

const Client = require('ssh2-sftp-client');
const Promise = require('bluebird');

const listFiles = async (sftp, directory) => sftp.list(`/${directory}`);

const pollSftpServer = async () => {
  // Instantiate here?
  const sftp = new Client();
  try {
    await Promise.delay(10000);
    await sftp.connect({
      host: '127.0.0.1',
      port: '2222',
      username: 'foo',
      password: 'pass',
    });
    const files = await listFiles(sftp, 'upload');
    console.log(files);
    return pollSftpServer();
  } catch (e) {
    console.error('caught error', e);
    return pollSftpServer();
  } finally {
    sftp.end();
  }
};

(() => {
  pollSftpServer();
})();