With the vast majority of countries (outside of the EU), the only time problems might arise is when a visa is sought for non-tourist purposes (e.g. to work in, or to emigrate to, that country).
Now the employment bit:
Convictions resulting in prison sentences become 'spent' as follows:
Sentence not exceeding 6 months > after 7 years (or 3� years if the person was under 18 when convicted)
Sentence exceeding 6 months but not exceeding 2�years > after 10 years (or 5 years if the person was under 18 when convicted)
Sentences over 2� years > Never
Note: No conviction can become 'spent' if the offender has another unspent conviction. So, if the person who was convicted of ABH commits another offence in the future (before the ABH conviction is 'spent'), the ABH offence won't become 'spent' until the other offence is also 'spent'.
Prior to a conviction becoming 'spent', a job applicant must always declare it when asked whether he has any criminal convictions. (Failure to do so is a criminal offence). Once a conviction is (for most purposes) 'spent', it only needs to be declared when applying for jobs which are exempted from the provisions of the Rehabilitation of Offenders Act (such as those working with, or alongside children or vulnerable adults).