UKH

How often should I have to tighten my drive chain? I have owned my bike from new for 6 months and done maybe 750 miles.

Its a 7 speed with one front sprocket if that makes any difference.

Any advice greatly appreciated.

I didn’t know tightening the chain was a thing tbh. 

Are you talking about a conventional drivetrain with a rear derailleur? Or a hub gear system?

Never, if you have a derailleur. It might be too long from the outset though.

7 speed nexus rear hub?  You need to pull the rear wheelback every few weeks and adjust the tension screws, keep the chain tight with about one cm up or down movement from middle of chain.

Maybe Mick means tightening the derailleur cable?

In which case - needing to tighten a new cable after ~100 miles is normal. The new cable 'settles in' and then needs tightening to retain crisp gear shifting.

If hes talking about a singlespeed then yes you may need to tension it, no idea when or how often though, you can also get a singlespeed tensioner that will do it for you. 

If you are talking about a standard 7x1 setup then no you dont tension it the spring in the derailleur will do that for you, but youll need to check your chain for wear (chain wear guide) and replace it when its around 75% worn.

Anything else Im just confused.

Yes its a standard set up with a derailleur. The concensus seems to be that the spring will sort out the tension for me...….thanks for the assistance.