If you feel you need a little help on the hills, then a different cassette with a greater range of ratios may be your answer. This customer is in training for an event later in the year and went down this route for his Boardman Bikes. New Shimano-Road Sora medium cage rear derailleur allied with a replacement chain and new 11-34T cassette means he has more flexibility when things start heading upwards. Not the cheapest, but cheaper than buying a new bike. In some cases it’s possible to retain the existing rear derailleur assuming it has the capacity for the larger cassette.