Lighthouse Studio is licensed with a specific capacity, counted in terms of stored data fields (not questions). The sizes are:
100 fields
500 fields
1000 fields
Unlimited fields
(If you purchase CBC, ACA, CVA, ACBC, or MaxDiff without an accompanying more expansive general survey license, you receive a 50 fields license capacity.)
Many question types use just one data field (variable) per question:
•Numeric
•Select (Radio button or Dropdown)
•Open-end
Some question types don't use any stored data fields:
•Text
•Terminate
Select-type questions with multiple responses use more than one data field (variable) per question, but we count these as just one stored data field toward your license capacity. The example below stores three data fields, but we count only one against your license capacity:
When grid questions are used, these can involve multiple data fields counted against your license. In the grid question below, there are four separate radio button variables, one variable for each row. This grid question below uses four data fields toward your license capacity.
This grid question below actually requires eight data fields to store a respondent's answers ("checked" vs. "not checked" for each box). But, we count only two data fields toward your license capacity in this case.
Looping has a huge effect on data field usage. If you loop over a question for each element of a list, then the number of variables used is multiplied by the list elements in the list.
The use of constructed lists can also greatly impact your data field usage. Consider a list of colors, such as:
1. Red
2. Green
3. Blue
4. Yellow
5. Purple
6. Peach
7. Pink
8. Orange
Let's also assume that we'll first ask respondents which colors they like (one data field counted toward your license capacity for this multiple-response question). Next, we construct a new list that includes only the colors each individual prefers. If we show only the colors preferred as part of a grid question and ask respondents to rate each preferred color, Lighthouse counts eight data fields toward your license, even though each individual would likely see just a subset of the eight colors in the follow-up question.
"Other specify" responses (in select-type questions) add an additional field per other specify and are counted as a question toward your license capacity.
Ranking questions count one question against the license for each rank that is cast. Therefore, if ranking ten options, ten questions are counted. If ranking just the top three of ten options, then three questions are counted.
When you click the 
icon from the Write Questionnaire dialog, Lighthouse prints the number of data fields used by each question in your survey.