b'So far as the period over which the operation needs to break even, the Guidance suggests a period of one to three years, but does permit a longer period at the authoritys discretion. A longer period might be required, for example, where the capital investment is higher and the local authority must justify its charging over the longer term in light of this Guidance. This approach allows a local authority greater flexibility to balance their accounts over a period of time and recognises the practical difficulties for a local authority in estimating the charges for a discretionary service at the outset. A local authority must offset any surplus or deficit in income as a result of any over or under recovery of charges when setting future charges for the discretionary services. In this way, the income generated by the discretionary service should equate to the cost of provision. Setting charges is not straightforward and in a political framework there will always be an argument for deferring decisions that might alienate a section of the community. A good example of this dilemma is parking charges where there is a trade-off between raising revenue and harming businesses because people no longer travel to the location to shop due to the parking charges. Most importantly, councils should ensure that: the choices they make are founded on good evidence about the likely impact of charging on patterns of service use by different groups of users; the estimation of net income receivable is well founded, and subject to risk assessment before being taken into account in the following years budget; the objectives of charging are clearly communicated to the public who should have the opportunity to hold the council to account for its decisions; and they evaluate whether the choices they have made are having the desired effect and to take appropriate action if not. Chapter 1 contains a suggested methodology for assessing the potential to generate additional income from charging.Pressures on local authorities to generate income 3.5 There are barriers to introducing charges and to increasing existing charges. Over three-quarters of councils identify the views of service users as a major or partial barrier to charging. The main concerns were that unpopular charges are sometimes seen as stealth taxes or as double payment for services. Research does suggest that people are more willing to pay charges where they can see what they are getting for their money and have a degree of choice or alternatively, where it means that their local council is able to maintain essential frontline services by charging for discretionary activities. 48'