Bilinguals vary immensely in their experience and use of language, encompassing myriad contexts of learning, relative abilities, domains associated with each language, and language mixing. The bilinguals designated Heritage Speakers, similarly, defy attempts to group them within a clearly delimited category. For researchers seeking to understand the linguistic experience, knowledge, and use of Heritage Speakers though use of experimental methods, this presents particular challenges. We present an overview of studies using eye-tracking and speech production and perception in order to illustrate how experimental methods rely strongly on a deep understanding of the language experience of the population being studied, sociolinguistic and other variation in their language use and that of those they communicate with, the experimental environment, and specific task demands. Interestingly, while these challenges are keenly felt by researchers interested in bilingualism and heritage language, they turn out to apply to language research in general, highlighting the complexity that is present, though perhaps not always so visible, even in apparently more homogeneous, monolingual speech communities.