When leading a tech team within a start-up it's very important to query all new development requests. While it's great to say yes and deliver every new feature, it could come at a cost further down the line. The business/customer may want a fully functional calendar feature with a rich UI, drag and drop, multi day appointments, export feature , etc. This may take 6 months + to develop. A to-do list with date/time tracking may suffice, which might only take 2 weeks development. Hammering the scope of the requirements down to a solution that meets the specific problem is what matters. It doesn't have to be cutting edge, innovative etc but it needs to be useful to solve the problem at hand.(Example taken from Shape Up)

The tech lead role is to make sure that adequate time is devoted to all aspects of the application, not just new development. While new development is very rewarding the housekeeping of the existing application is just as important. Keeping existing customers is easier than getting new customers, industry research has proven that. Performance, reliability and good will with the end users is vital. New developments should be high energy sprints of no more than 4-8 weeks, once finished some down time to recover and prepare for the next sprint. Within this down time gives an opportunity to do some much needed housekeeping. Some parts of the system may need upgrading, bug fixing, optimisation/scaling and developers may need some time to refactor some existing code they never got around to.

Getting the balance right will help support the business growing which is in everyones interest.