A vapour provision system comprising: a heating element for generating a vapour from a vapour precursor material; and control circuitry configured to provide power for the heating element for performing a heating operation to generate the vapour and to compare a measurement of a resistance value for the heating element for the heating operation with a baseline resistance value for the heating element for use in detecting a fault condition, wherein the control circuitry is further configured to: establish the baseline resistance value for a first heating operation by making a measurement of a first resistance value for the heating element; and establish the baseline resistance value for a second, subsequent, heating operation by making a measurement of a second resistance value for the heating element if more than a predetermined period of time has elapsed between the first heating operation and the second heating operation, and otherwise using the same baseline resistance value as for the first heating operation, characterized in that the control circuitry is further configured to make a measurement of a second resistance value for the heating element for the second heating operation if less than the predetermined period of time has elapsed between the first heating operation and the second heating operation, and is further configured in that case to establish the baseline resistance value based on the second resistance value if the second resistance value is lower than the first resistance value, and otherwise use the same baseline resistance value as for the first heating operation. a heating element for generating a vapour from a vapour precursor material; and control circuitry configured to provide power for the heating element for performing a heating operation to generate the vapour and to compare a measurement of a resistance value for the heating element for the heating operation with a baseline resistance value for the heating element for use in detecting a fault condition, wherein the control circuitry is further configured to: establish the baseline resistance value for a first heating operation by making a measurement of a first resistance value for the heating element; and establish the baseline resistance value for a second, subsequent, heating operation by making a measurement of a second resistance value for the heating element if more than a predetermined period of time has elapsed between the first heating operation and the second heating operation, and otherwise using the same baseline resistance value as for the first heating operation, characterized in that the control circuitry is further configured to make a measurement of a second resistance value for the heating element for the second heating operation if less than the predetermined period of time has elapsed between the first heating operation and the second heating operation, and is further configured in that case to establish the baseline resistance value based on the second resistance value if the second resistance value is lower than the first resistance value, and otherwise use the same baseline resistance value as for the first heating operation. establish the baseline resistance value for a first heating operation by making a measurement of a first resistance value for the heating element; and establish the baseline resistance value for a second, subsequent, heating operation by making a measurement of a second resistance value for the heating element if more than a predetermined period of time has elapsed between the first heating operation and the second heating operation, and otherwise using the same baseline resistance value as for the first heating operation, characterized in that the control circuitry is further configured to make a measurement of a second resistance value for the heating element for the second heating operation if less than the predetermined period of time has elapsed between the first heating operation and the second heating operation, and is further configured in that case to establish the baseline resistance value based on the second resistance value if the second resistance value is lower than the first resistance value, and otherwise use the same baseline resistance value as for the first heating operation.