1. A computing system comprising: a network interface configured to receive data from a plurality of assets; a data intake system configured to ingest data received from the plurality of assets; at least one processor; a non-transitory computer-readable medium; and program instructions stored on the non-transitory computer-readable medium that are executable by the at least one processor to cause the computing system to: based on historical operating data for a plurality of assets, define a predictive model that is configured to (a) receive sensor data for an asset as input, (b) for each of at least two failure types from a group of failure types related to mechanical operation, make a respective prediction of whether the failure type is likely to occur at the asset in the future, and (c) based on the respective predictions, determine and output a health metric indicating whether at least one failure type from the group of failure types related to mechanical operation is predicted to occur at the asset in the future, wherein the historical operating data comprises (i) historical abnormal-condition data for the plurality of assets that indicates past occurrences of abnormal conditions that are associated with the group of failure types and (ii) historical sensor data for the plurality of assets that indicates sensor measurements associated with the past occurrences of abnormal conditions; operate in a first mode in which the data intake system ingests operating data received from a given asset of the plurality of assets at a first ingestion rate, wherein the operating data comprises data related to the mechanical operation of the given asset that includes abnormal-condition data and sensor data; while operating in the first mode, (a) receive operating data from the given asset; and (b) ingest at least a portion of the received operating data at the first ingestion rate, wherein the ingested portion of the received operating data includes ingested sensor data for the given asset; apply the predictive model to the ingested sensor data and thereby determine a health metric for the given asset that indicates whether at least one failure type from the group of failure types related to mechanical operation is predicted to occur at the given asset in the future; compare the health metric for the given asset to a threshold condition that defines whether an asset is considered to be in a state of impending failure and thereby make a determination that the health metric satisfies the threshold condition such that the given asset is considered to be in a state of impending failure; in response to the determination, transition from operating in the first mode to operating in a second mode in which the data intake system ingests operating data from the given asset at a second ingestion rate that is higher than the first ingestion rate; and while operating in the second mode, (a) receive operating data from the given asset and (b) ingest at least a portion of the received operating data at the second ingestion rate, wherein the ingested operating data comprises data related to the mechanical operation of the given asset that includes abnormal-condition data and sensor data.