In the United States in this day and age, there is exhaustive national polling in Presidential election races (including Presidential primary races) and is a significant amount of polling done in top of the ticket statewide office races (state level Presidential election polls, U.S. Senate race poll, and Governor's race polls). There is also frequency at least some statewide polling on at least the most high profile and controversial ballot issues.
But, there is generally little or no polling done on ballot issues that are not statewide, on down ticket statewide candidate races (e.g. state attorneys-general, secretaries of state, state treasurers, and various state board memberships).
There is surprisingly little polling done in races for the U.S. House of Representatives, and there is basically no polling done in races for state legislative seats and for local government offices, or even for regional government offices (e.g. in Colorado, seats on the Board of the Regional Transportation District and District Attorney elections).
A quite modest investment in additional polling would greatly improve the amount of publicly available information about the probable political consequences of upcoming elections.
The amount of information available from additional polling also wouldn't have to be very expensive to produce a lot of valuable information.
For example, an issue in the 2016 election that matters a great deal to pretty much everyone in Colorado is which party will control the state house and state senate in the Colorado General Assembly after the election.
It wouldn't be too hard to get good information on this question from polling. Half of the 35 seats in Colorado's state senate are not before the voters in 2016 since this body has four year terms with half of the seats before the voters every two years. Voters cast ballots in all 65 seats of Colorado's state house every two years.
But, while there are 82-83 seats in play in the Colorado General Assembly every two years, previous election results (particularly in cases where there is an incumbent running), the fact that not every seat has a candidate from both major political parties, voter registration data in each state legislative district in an era where gerrymandering to protect incumbents is the norm, and campaign finance data from each state legislative race, mean that only a small share of these seats (probably less than ten or twelve a year) are seriously in play in any given year.
A couple of 300 likely voter surveys over the course of an election season in the ten or twelve most competitive state legislative seats would dramatically improve the accuracy of predictions of the post-election partisan divide of the state legislature, and this general approach could work in almost every state, as well as in elections for the U.S. House of Representatives.
Similar polling even a single time with similar sample sizes, even once over the course of an election year of local and regional ballot issues of consequence could likewise make a big difference to people interested in accurately predicting the probable nature of political landscape after an election.
There are less than 40 to 60 races for the U.S. House of Representatives that are remotely competitive in any given year, and given that these races are also conducted every two years, predominately involve incumbent candidates, can be analyzed with publicly available campaign finance data, and are held in highly gerrymandered seats, it isn't terribly difficult to quite accurately establish a list of viably contested seats. And, again, just two or three polls of a few hundred likely voters each conducted after primaries are complete in these races could dramatically increase the accuracy of predictions about the future partisan control of the U.S. House of Representatives, which is information of wide utility to a wide variety of people and organizations within and outside the United States. In principle, every single Congressional race has a potential significant impact on everyone in the world who is directly or indirectly impacted by federal government policy. The partisan control of Congress is almost as important, if not more so in many cases, on questions of national policy over an extremely broad range of issues, as who wins the Presidency.
In sum, conducting polling a couple of times in about 600 key candidate races each election cycle, and perhaps 300 polls an election cycle in notable regional and local ballot issue conducts, for a total investment of about 1500 polls with 300 likely voters each, involving less than 450,000 survey sessions of likely voters (less because some of the surveys could have partially overlapping samples, such as surveys of voters who live in both a surveyed state house and a surveyed state senate seat, which would be common since competitive seats are often geographically overlapping), plus additional calls to people who are ultimately determined to be outside the survey area, could dramatically improve the quality of the data available to political analysts.
This might cost $1 million to $3 million per election cycle, which is a pittance next to the amount of money spent each election year in the United States on election campaigns, political analysis, and lobbying. And, the highly geographically dispersed nature of this polling effort, as well as the fact that in our system of federalism no election crosses state lines (even Presidential elections are strictly speaking elections in each state for Presidential electors pledged to particular candidates), would facilitate cost sharing in exchange for co-branding the results when they are announced with the financial sponsors of these polls. Splitting the cost 50 ways into bundles for each state would bring the cost of this effort per state to something on the order of $20,000-$60,000 each per two year election cycle - something in the ballpark of what a single college or university in a state could afford (with some of funding with these kinds of sponsors coming "in kind" in higher educational institutions from social science student volunteers learning about research methods first hand, as several prominent colleges already do with great P.R. returns for the institutions involved).
This data would also make existing survey data during election years richer and more robust because the data when integrated with existing political polling, would tell us more about the political environment in which top of the ticket races are being conducts and would make it easier to identify outlier polling results in top of the ticket races.
In my view, this would be money well spent. Better polling of these races would also call more attention to them in a manner that would generally benefit the health of our democracy, because hose race coverage provides a natural starting point for media coverage of these political races and media coverage of political races increases public awareness of these races and improves the quality of the decisions made by the public in these races when the time comes for otherwise undecided voters in these races to vote.