I have about £30000 that I could start investing now in a tax efficient way (UK ISA, which means essentially zero tax).
Since the markets are at an all-time high right now, I am thinking it would perhaps be a good strategy to spread this investment over the next 18-24 months but I am not sure what would actually be the optimal period of time over which to spread the investment.
I'm thinking about putting money on a monthly basis in a couple of investment trusts such as the "Bankers Investment Trust" or "Scottish Mortgage". I also expect to have saved more by the time I have invested the amount I have now so I could potentially keep going with the monthly investments in the trusts.
I am aware that trying to time market downturns is impossible, but is there still some way to determine over how many months I should ideally spread my investment on? At the moment, I would say I have a 7-10 years investment goal.