My primary motivation to train indoors is to maintain and/or improve fitness over the winter months.
In my opinion, the benefits of indoor training during early morning sessions are do-able and convenient on an indoor trainer. Poor weather won’t dictate the time/distance spent in the saddle. Software such as Zwift provides a sociable element to your indoor training and plenty of numbers to analyse and improve upon (power, watts per kilo, HR, av. speed, etc). Preparation for an indoor session is quick as there’s less kit to put on. Less bike maintenance/cleaning after a training ride also.
The biggest benefit for me personally is the uninterrupted continuity of a structured training plan with all the numbers I need to monitor my progress.
Think about what you want to achieve over the winter months and build an indoor setup from there. If you just want to spin the legs for 30min three times a week use an old / 2nd hand bike on a resistance based turbo trainer. You can pick up a second-hand trainer on eBay for less than £40. A bit of music and you’re well away. You can also set your Garmin (or similar) to indoor mode, pick up a cheap cadence monitor and still upload your rides to Strava.
If you’re like me and need the numbers along with a visual aid for some serious training, you may want to consider upping your budget to a smart trainer and a Zwift (or similar) subscription. Smart trainers start around £450 and rise to £1.5K (do your research for the best model for your needs). Dont buy a 2nd hand smart trainer. You’ll want warrenty just incase it fails on you. Zwift will cost £12pm. You’ll also need a decent laptop and ANT adaptor so the software can detect your trainer output.
For me Zwift is well worth the money as it opens a world of virtual cycling that gives you anything from personalised training plans to elite races. I was an original Zwifter and it’s improved year on year.
Whatever set up you go for, get a fan and drink plenty of water as there’s no breeze to compensate for all your hard work!
I’m sure you’ll get lots of opinions on this subject but at the end of the day whichever set up you go for it’s a great way to maintain that fitness you worked so hard for over the summer.